JP2019046668A - Spacer, led surface light source device, and led image display device - Google Patents

Abstract

To provide a spacer which achieves excellent handling ability and strength, can be used with a housing having a bottom part with an inner bottom surface curved into a convex shape, and can inhibit deterioration of utilization efficiency of light from LED elements when installed in the housing, and to provide an LED surface light source device and an LED image display device which include the spacer.SOLUTION: A first spacer 60 is disposed between an LED mounting substrate and a first optical sheet, can be curved, and includes: two or more openings which penetrate in a first direction FD that is a thickness direction of the first spacer 60; a wall part 62 which partitions the openings from each other and surrounds at least one of the openings; and multiple columnar parts 63 which protrude from a first surface 62A and are arranged in a second direction SD so as to be spaced away from each other. When the first spacer 60 is curved at a predetermined curvature radius so that the second surface 62B is made into a concave shape, a distance d3 between tip parts 63A of the adjacent columnar parts 63 is larger than or equal to a distance d4 between root parts 63B.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a spacer, a surface light source device, and an image display device.

  2. Description of the Related Art An LED image display apparatus, which has been widely spread in recent years, generally comprises a display screen such as a liquid crystal display panel and an LED surface light source apparatus for illuminating the display screen from the back side. Currently, in LED image display devices, edge light type LED surface light source devices are usually used in many cases, but from the viewpoint of brightness, using direct type LED surface light source devices is being studied.

  In the direct type LED surface light source device, an optical sheet is disposed on the LED element from the viewpoint of improving the in-plane uniformity of the luminance on the light emitting surface of the LED surface light source device. As such an optical sheet, for example, a resin reflective sheet such as white that reflects light from the LED element, an opening pattern whose opening gradually becomes larger from immediately above the LED element toward the periphery of the LED element There are cases where the formed light transmission and reflection sheet is used (see Patent Document 1). By using a light transmitting / reflecting sheet having such an opening pattern, light on the LED element can be reflected and diffused to the periphery and emitted from the surrounding openings, thus improving the in-plane uniformity of luminance. It can be done.

  In order to improve the in-plane brightness uniformity by the optical sheet, it is necessary to separate the optical sheet from the LED mounting substrate on which the LED element is mounted. Therefore, a plurality of columnar spacers are generally disposed between the LED mounting substrate and the optical sheet to separate the optical sheet from the LED mounting substrate.

JP, 2010-272245, A

  However, such columnar spacers have to be disposed one by one, which causes a problem of poor handling. In addition, the columnar spacer also has a problem of being inferior in strength. For this reason, development of a spacer that replaces the columnar spacer is desired.

  By the way, although such a spacer etc. is stored in the case which has a bottom part and an opening, for example, when incorporating an LED image display device provided with such a spacer etc in vehicles, such as a car, thickness was limited Among them, it is considered to use a housing with a curved bottom in order to make the best use of space and the like. Specifically, for example, it has been considered to use a housing whose bottom is curved such that the inner bottom is convex.

  When a housing having such a curved bottom is used, the LED mounting substrate, the spacer, and the like are required to be along the inner bottom surface of the bottom. Here, with regard to the LED mounting substrate, by using a flexible wiring substrate as a wiring substrate of the LED mounting substrate, it is possible to cope with such a housing, but with regard to the spacer, it is still possible to cope with such a housing. Not. Furthermore, when using such a housing | casing, since light utilization efficiency will fall if the light from a LED element is interrupted | blocked by a spacer, it is also calculated | required that the fall of light utilization efficiency can be suppressed.

  The present invention has been made to solve the above problems. That is, a spacer that is excellent in handling property and strength, can correspond to a case having a bottom with a convexly curved inner bottom surface, and can suppress a decrease in the utilization efficiency of light from the LED element when installed in such a case , And an LED surface light source device and an LED image display device provided with the same.

  According to one aspect of the present invention, an LED mounting substrate including a flexible wiring substrate and a plurality of LED elements mounted on one surface of the flexible wiring substrate, and an optical sheet disposed on the LED device side A bendable spacer which is used in an LED surface light source device, and which is disposed between the LED mounting substrate and the optical sheet, and which penetrates two or more in a first direction which is a thickness direction of the spacer An opening, a wall dividing the opening and surrounding the periphery of the at least one opening, and protruding from a first surface of the wall positioned in the first direction and separated from each other And a plurality of columnar portions aligned in a second direction along the first surface, and the spacer is provided on the wall portion with a concave second surface opposite to the first surface. The first outer edge located on the second direction side of the wall and the second outer edge located on the wall with a predetermined radius of curvature, and the first outer edge Distance between the tips of adjacent ones of the pillars in the second direction when it is curved between the second outer edge opposite to the one and the distance between the roots of the adjacent pillars in the second direction Thus, a spacer is provided.

  In the above-mentioned spacer, in a state before bending, in the 2nd direction, the distance between the tip parts of the adjacent pillars may be smaller than the distance between the roots of the adjacent pillars.

  In the spacer, in the state before bending, in the second direction, the lengths of the columnar portions are substantially equal, and the heights of the columnar portions are from the central portion of the wall portion to the first outer edge portion And may gradually decrease toward the second outer edge.

  In the spacer, in the second direction before bending, the lengths of the pillars gradually increase from the center of the wall to the first outer edge and the second outer edge in the second direction, And the height of each of the pillars may be gradually increased from the central portion to the first outer edge portion and the second outer edge portion.

  According to another aspect of the present invention, there is provided an LED mounting board comprising a flexible wiring board and a plurality of LED elements mounted on one surface of the flexible wiring board, and an optical sheet disposed on the LED element side A spacer which is used in an LED surface light source device and which is disposed between the LED mounting substrate and the optical sheet, and which has two or more openings penetrating in a first direction which is a thickness direction of the spacer; A wall part between the openings and surrounding the periphery of the at least one opening, and the first part of the wall part protruding from a first surface positioned in the first direction and separated from each other And a plurality of columnar portions arranged in a second direction along the first surface, wherein the spacer is configured such that a second surface of the wall opposite to the first surface is concaved. A first outer edge located on the second direction side of the wall and a second outer edge located on the second direction side of the wall with a predetermined radius of curvature, and opposite to the first outer edge Curved with the second outer edge on the side, and in the second direction, the distance between the tips of adjacent ones of the pillars is equal to or greater than the distance between the roots of the adjacent pillars , A spacer is provided.

  In the spacer, in the second direction, the heights of the pillars may be gradually lowered from the central portion of the wall portion to the first outer edge portion and the second outer edge portion.

  In the spacer, in the second direction, the height of each of the pillars may be gradually increased from the central portion of the wall to the first outer edge and the second outer edge.

  In the spacer, the heights of the columnar portions may be substantially equal in the second direction.

  In the above spacer, the spacer may be made of polycarbonate resin.

  In the spacer, the wall portion may have a lattice shape or a honeycomb shape.

  According to another aspect of the present invention, there is provided a housing including a bottom, and a plurality of flexible wiring boards and a plurality of flexible wiring boards and a plurality of the wiring boards mounted on the side opposite to the bottom side. An LED mounting substrate including an LED element, a first optical sheet disposed on the LED element side, and a first spacer disposed between the LED mounting substrate and the first optical sheet The bottom portion of the housing is formed between a first edge of the bottom portion and a second edge opposite to the first edge such that the inner bottom surface of the bottom portion is convex. The LED mounting substrate is curved and disposed along the inner bottom surface of the bottom portion, the first spacer is the spacer, and the spacer is the first surface of the wall portion. The opposite second surface is concave and An LED surface light source device which is curved between the first outer edge of the wall and the second outer edge of the wall with the predetermined curvature radius along the surface of the ED mounting substrate Is provided.

  According to another aspect of the present invention, there is provided a housing comprising a bottom and an opening, and an LED comprising a plurality of LED elements disposed in the housing and mounted on one surface of a flexible wiring board and the wiring board. A mounting substrate, a first optical sheet disposed on the side of the LED element, and a first spacer disposed between the LED mounting substrate and the first optical sheet; The bottom is curved between a first edge of the bottom and a second edge opposite the first edge such that the inner bottom surface of the bottom is convex. The LED mounting substrate is disposed along the inner bottom surface of the bottom portion, the first spacer is the spacer, and the spacer is a surface of the wall of the LED mounting substrate. LED surface light source located along Location.

  In the LED surface light source device, the first optical sheet includes a plurality of divided regions in a plan view, and the plurality of divided regions transmit a part of light from the LED element. And a plurality of reflecting portions for reflecting a part of the light from the LED element, and an aperture ratio which is an area ratio of the transmitting portion in each of the sectioned regions is from the central portion of the divided region to the sectioned region It may be gradually increasing towards the outer edge of the

  In the surface light source device, the second optical sheet disposed on the light emitting side of the first optical sheet, the outer peripheral surface of the first optical sheet, and the outer peripheral surface of the first spacer are disposed so as to surround them. And a frame-like second spacer for separating the second optical sheet from the first optical sheet.

  According to another aspect of the present invention, there is provided an LED image display device comprising the LED surface light source device and a display panel disposed closer to the viewer than the LED surface light source device.

  According to one aspect of the present invention, it is possible to cope with a case having excellent handleability and strength, and an inner bottom surface having a convex curved bottom, and when installed in such a case, light from the LED element It is possible to provide a spacer capable of suppressing a decrease in utilization efficiency. Moreover, according to the other aspect of this invention, the LED surface light source device and LED image display apparatus provided with such a spacer can be provided.

It is a perspective view of the LED image display apparatus which concerns on embodiment. It is a schematic block diagram of the LED image display apparatus which concerns on embodiment. It is an expanded sectional view of a part of LED surface light source device concerning an embodiment. It is a top view of the 1st optical sheet shown by FIG. It is a top view of the other 1st optical sheet which concerns on embodiment. Figure 2 is a perspective view of the first spacer shown in Figure 1; FIG. 7 is a side view of the first spacer shown in FIG. 6; FIG. 7 is a side view of the first spacer shown in FIG. 6 before bending. It is a top view which shows the arrangement | positioning relationship of the 1st optical sheet and 1st spacer which are shown by FIG. It is a figure which shows the other arrangement | positioning place of the columnar part which concerns on embodiment. It is a figure which shows the other shape of the columnar part which concerns on embodiment. It is a figure which shows the other shape of the front end surface of the columnar part which concerns on embodiment. It is a top view of other 1st spacers concerning an embodiment. It is a top view of other 1st spacers concerning an embodiment. It is a side view of other 1st spacers concerning an embodiment. FIG. 16 is a side view of the other first spacer shown in FIG. 15 before bending. It is a side view of other 1st spacers concerning an embodiment. FIG. 18 is a side view of another first spacer shown in FIG. 17 before bending. It is a perspective view of the other 1st spacer which concerns on embodiment. FIG. 20 is a side view of the first spacer shown in FIG. 19; It is a top view which shows the arrangement | positioning relationship of the 1st spacer shown by FIG. 1, and a 2nd spacer. It is sectional drawing of the lens sheet shown by FIG.

  Hereinafter, a spacer, a direct-type surface light source device, and an image display device according to an embodiment of the present invention will be described with reference to the drawings. In the present specification, "LED" means a light emitting diode. Also, terms such as "sheet", "film", "plate" and the like are not distinguished from one another based only on the difference in designation. Thus, for example, "sheet" is used to include members such as a film or a plate. FIG. 1 is a perspective view of the LED image display apparatus according to the present embodiment, FIG. 2 is a schematic configuration view of the LED image display apparatus according to the present embodiment, and FIG. 3 is an LED surface light source apparatus according to the present embodiment. FIG. FIG. 4 is a plan view of the first optical sheet shown in FIG. 1, and FIG. 5 is a plan view of another first optical sheet according to the present embodiment. 6 is a perspective view of the first spacer shown in FIG. 1, FIG. 7 is a side view of the first spacer shown in FIG. 6, and FIG. 8 is a curve of the first spacer shown in FIG. It is a front side view. FIG. 9 is a plan view showing the arrangement of the first optical sheet and the first spacer shown in FIG. FIG. 10 is a view showing another arrangement portion of the columnar portion according to the present embodiment, FIG. 11 is a view showing another shape of the columnar portion according to the present embodiment, and FIG. 12 is a column according to the present embodiment It is a figure which shows the other shape of the front end surface of a part. 13 and 14 are plan views of other first spacers according to the embodiment. FIG. 15 is a side view of another first spacer according to the embodiment, and FIG. 16 is a side view of the other first spacer shown in FIG. 15 before bending. FIG. 17 is a side view of another first spacer according to the embodiment, and FIG. 18 is a side view of the other first spacer shown in FIG. 17 before bending. FIG. 19 is a perspective view of another first spacer according to the present embodiment, and FIG. 20 is a side view of the first spacer shown in FIG. FIG. 21 is a plan view showing the arrangement of the first and second spacers shown in FIG. 1, and FIG. 22 is a cross-sectional view of the lens sheet shown in FIG.

<<<< LED image display device >>
The LED image display device 10 shown in FIGS. 1 and 2 includes a direct-type LED surface light source device 20 and a display panel 120 disposed closer to the viewer than the LED surface light source device 20. The LED image display device 10 is entirely curved such that the display surface 10A has a convex shape.

<<< Display panel >>>
The display panel 120 shown in FIGS. 1 and 2 is a liquid crystal display panel, and includes a polarizing plate 121 disposed on the light incident side, a polarizing plate 122 disposed on the light outgoing side, a polarizing plate 121, and a polarizing plate 122. And a liquid crystal cell 123 disposed between them. As the polarizing plates 121 and 122 and the liquid crystal cell 123, known polarizing plates and liquid crystal cells can be used.

<<< LED surface light source device >>>
As shown in FIG. 2, the LED surface light source device 20 includes a housing 30, an LED mounting substrate 40, a first optical sheet 50, a first spacer 60, a second optical sheet 70, And a spacer 80 of two. In addition, the LED surface light source device 20 further includes a lens sheet 90 and a reflective polarization separation sheet 100 laminated on the second optical sheet 70. The LED surface light source device 20 may include the housing 30, the LED mounting substrate 40, the first optical sheet 50, and the first spacer 60, and the second optical sheet 70 and the second spacer 80. The lens sheet 90 or the reflective polarization separation sheet 100 may not be provided. The first spacer 60 is used in a surface light source device including an LED mounting substrate and an optical sheet. In the LED surface light source device 20, the optical sheet is the first optical sheet 50.

  Since the in-vehicle surface light source device is disposed in a very narrow space in the vehicle, it is desired to make it thinner than a general surface light source device. Therefore, the total thickness of the LED surface light source device 20 is preferably 15 mm or less, and more preferably 10 mm or less, from the viewpoint of achieving thinning. The total thickness of the “LED surface light source device” means the distance from the outer bottom surface 32D of the housing 30 shown in FIG. 2 to the surface 100A of the reflective polarization separation sheet 100.

<< case >>
The housing 30 includes a housing space 31 for housing the LED mounting substrate 40 and the like, a bottom 32, a side 33 rising from the bottom 32, and an opening 34 provided at a position facing the bottom 32. The bottom 32 is curved between a first edge 32A of the bottom 32 and a second edge 32B opposite to the first edge 32A. Specifically, the inner bottom surface 32C of the bottom portion 32 is convex, and the outer bottom surface 32D of the bottom portion 32 is concave. The opening 34 is for emitting the light from the LED element 42 from the housing 30. The shape of the opening 34 is not particularly limited, and may be, for example, rectangular or circular.

  The housing 30 includes a housing main body 35 having a housing space 31, and a frame-like lid 36 covering the housing space 31 of the housing main body 35 and having an opening 34. In the case 30, the inner bottom surface 32C of the case 30 is the inner bottom surface of the case main body 35, and the inner side surface of the case 30 is the inner side surface of the case main body 35.

  The housing 30 (the housing body 35 and the lid 36) is preferably made of metal. In particular, by forming the case body 35 from metal, the case body 35 also functions as a heat dissipation structure, so the heat from the LED element 42 can be dissipated efficiently. The metal is not particularly limited, and examples thereof include aluminum and the like.

<< LED mounting board >>
The LED mounting substrate 40 is disposed along the curved bottom 32 of the housing 30. Specifically, since the inner bottom surface 32C of the bottom portion 32 of the housing 30 is convex, the LED mounting substrate 40 is arranged to be curved along the inner bottom surface.

  As shown in FIG. 2 and FIG. 3, the LED mounting substrate 40 is mounted on the flexible wiring substrate 41 and one surface 41A of the flexible wiring substrate 41 (hereinafter, this surface is referred to as “surface”). And the LED element 42 of FIG. In the LED mounting substrate 40, by using a flexible wiring substrate, the LED mounting substrate 40 can be disposed along the inner bottom surface 32C. As shown in FIGS. 2 and 3, the LED mounting substrate 40 has a surface (hereinafter referred to as “rear surface”) 41 B of the flexible wiring substrate 41 opposite to the surface 41 A on which the LED element 42 is mounted. Are disposed in the housing 30 so as to be located on the inner bottom surface 32C side of the housing 30.

<Flexible wiring board>
The flexible wiring board 41 is disposed along the inner bottom surface 32C of the housing 30. The back surface 41 B of the flexible wiring board 41 is preferably in contact with the inner bottom surface 32 C of the housing 30. When the back surface 41 B of the flexible wiring board 41 contacts the inner bottom surface 32 C of the housing 30, the heat of the flexible wiring board 41 and the like can be efficiently dissipated to the housing 30 side. In this specification, "the back surface of the wiring substrate is in contact with the inner bottom surface of the housing" is not limited to the case where the back surface of the wiring substrate is in direct contact with the inner bottom surface of the housing. This concept also includes the case where a substantially negligible layer such as a double-sided tape, an adhesive, or an adhesive is interposed between the inner bottom surface of the housing and the double-sided tape.

  In the present specification, "flexible" means having flexibility, and "flexible wiring substrate" generally means a flexible and bendable wiring substrate. In the present specification, "flexible" means curving so that at least the radius of curvature is 1 m. The flexible wiring substrate is curved such that the radius of curvature is preferably 50 cm, more preferably 30 cm, still more preferably 10 cm, particularly preferably 5 cm.

  In the flexible wiring board 41, as shown in FIG. 3, the resin film 43, the metal wiring portion 44, the insulating protective film 45, and the reflective layer 46 are directed in this order toward the first optical sheet 50. Is stacked on. However, the flexible wiring substrate 41 may not have the insulating protective film 45 or the reflective layer 46. The metal wiring portion 44 is preferably bonded to the resin film 43 by a dry lamination method via the adhesive layer 47. Furthermore, the metal wiring portion 44 is electrically connected to the LED element 42 via the solder layer 48.

(Resin film)
The resin film 43 has flexibility. The resin film 43 is a film bent so that the radius of curvature is preferably 50 cm, more preferably 30 cm, still more preferably 10 cm, particularly preferably 5 cm.

  The resin film 43 can be formed using a known thermoplastic resin. The thermoplastic resin used as the material of the resin film 43 is preferably one having high heat resistance and insulation. As such a resin, polyimide (PI) and polyethylene naphthalate (PEN), which are excellent in heat resistance, dimensional stability at heating, mechanical strength, and durability, can be used. Among these, polyethylene naphthalate (PEN), in which heat resistance and dimensional stability are improved by performing heat resistance improvement treatment such as annealing treatment, can also be preferably used. Further, polyethylene terephthalate (PET) whose flame retardancy has been improved by the addition of a flame retardant inorganic filler or the like can also be selected as a resin for forming a resin film.

  As the thermoplastic resin for forming the resin film 43, one having a heat shrinkage start temperature of 100 ° C. or higher, or one whose heat resistance is improved to be 100 ° C. or higher by the above-mentioned annealing treatment or the like is used. Is preferred. The “heat shrinkage start temperature” in this specification means that a sample film made of a thermoplastic resin to be measured is set in a thermomechanical analysis (TMA) device, and a 1 g load is applied to raise the temperature to 120 ° C. Heat up to ° C, measure the amount of contraction (in%) at that time, and output the data to record the temperature and the amount of contraction. Read the temperature away from the 0% baseline due to contraction from that graph. As the heat shrinkage start temperature. In addition, let heat contraction start temperature be an arithmetic mean value of the value obtained by measuring 3 times.

  In general, the temperature around the LED element may reach a temperature of about 90 ° C. due to the heat from the LED element. From this viewpoint, it is preferable that the thermoplastic resin forming the resin film 43 has heat resistance equal to or higher than the above temperature.

The resin film 43 is required to be a resin having a high insulation property that can provide the flexible wiring board 41 with the required insulation property. Therefore, the volume specific resistivity of the resin film 43 is preferably 10 ¹⁴ Ω · cm or more, and more preferably 10 ¹⁸ Ω · cm or more. The volume resistivity can be measured by a method in accordance with JIS C2151: 2006. The volume resistivity is randomly measured at 10 points, and is taken as the arithmetic mean value of the measured 10 volume resistivity.

  The thickness of the resin film 43 is not particularly limited, but it is about 10 μm or more and 500 μm or less from the viewpoint of not being a bottleneck as a heat radiation path, having heat resistance and insulation, and balance of manufacturing costs. Is preferred. The thickness range is also preferable from the viewpoint of maintaining good productivity in the roll-to-roll manufacturing. The thickness of the resin film 43 can be obtained by measuring the thickness at any 10 points using a thickness measuring device (product name “Digimatic indicator IDF-130”, manufactured by Mitutoyo) and calculating the average value thereof I assume. The lower limit of the thickness of the resin film 43 is preferably 50 μm or more, and the upper limit of the thickness of the resin film 43 is preferably 250 μm or less.

(Metal wiring section)
The metal wiring portion 44 is provided closer to the LED element 42 than the resin film 43 and is electrically connected to the LED element 42. The metal wiring portion 44 can be formed by patterning a metal foil or the like.

  The thermal conductivity λ of the metal constituting the metal wiring portion 44 is preferably 200 W / (m · K) or more and 500 W / (m · K) or less. The thermal conductivity λ can be measured, for example, using a thermal conductivity meter (product name “QTM-500”, manufactured by Kyoto Denshi Kogyo Co., Ltd.). The thermal conductivity λ is an arithmetic mean value of the values obtained by measuring three times. The lower limit of the thermal conductivity is more preferably 300 W / (m · K) or more, and the upper limit is preferably 500 W / (m · K) or less. In the case of copper, the thermal conductivity λ is 403 W / (m · K).

3.00 * 10 < ^-8 > (ohm) m or less is preferable, and, as for the electrical resistivity R of the metal which comprises the metal wiring part 44, 2.50 * 10 < ^-8 > (ohm) m or less is more preferable. The electrical resistivity R can be measured using an electrometer (product name “6517 B type electrometer”, manufactured by Keithley). The electrical resistivity R is an arithmetic mean value of values obtained by measuring three times. In the case of copper, the electrical resistivity R is 1.55 × 10 ⁻⁸ Ωm.

  For example, when the metal wiring portion 44 is formed of copper foil, it is possible to achieve both heat dissipation and electrical conductivity at a high level. More specifically, since the heat dissipation from the LED element is stabilized and the increase in the electrical resistance can be prevented, the variation in light emission among the LEDs becomes small, and the stable light emission of the LED becomes possible. In addition, the lifetime of the LED element is also extended. Furthermore, since deterioration of peripheral members such as a resin film due to heat can be prevented, the product life of the image display device incorporating the surface light source device can also be extended.

  As an example of the metal which forms the metal wiring part 44, metals, such as aluminum, gold | metal | money, silver other than said copper, can be mentioned.

  The metal wiring portion 44 is an electrodeposited copper foil, and the ten-point average roughness Rz of the surface on the resin film 43 side of the metal wiring portion 44 is more preferably 1.0 μm or more and 10.0 μm or less. By setting the ten-point average roughness Rz within the above range, the surface area of the surface on the resin film 43 side of the metal wiring portion 44 can be particularly increased, and the heat dissipation can be further enhanced. Moreover, since this surface is an uneven surface, the adhesion with the resin film 43 can be further improved, and the heat dissipation can also be improved by this. The rough side (mat surface side) of the electrodeposited copper foil can be suitably used as the surface of the electrodeposited copper foil having such a ten-point average roughness Rz. The ten-point average roughness Rz can be measured, for example, using a surface roughness measuring instrument (product name “SE-3400”, manufactured by Kosaka Laboratory Ltd.) in accordance with JIS B0601: 1999. The ten-point average roughness Rz is an arithmetic mean value of the values obtained by measuring three times.

  The arrangement of the metal wiring portion 44 is not limited to a specific arrangement as long as the LED elements 42 can be conducted, preferably the LED elements 42 can be arranged in a matrix. However, in the flexible wiring board 41, the metal wiring portion 44 preferably covers 80% or more, more preferably 90%, and most preferably 95% or more of one surface of the resin film 43. Is preferred. Thus, the LED elements 42 can be disposed at high density, and the generated excess heat can be sufficiently diffused quickly through the metal wiring portion 44 and can be dissipated to the outside via the resin film 43. Therefore, the LED surface light source device 20 having excellent heat dissipation can be obtained.

  The thickness of the metal wiring portion 44 may be appropriately set according to the magnitude of the current resistance required of the flexible wiring substrate 41 and the like, and is not particularly limited, but may be 10 μm to 50 μm as an example. It is preferable that the thickness of the metal wiring part 44 is 10 micrometers or more from a viewpoint of heat dissipation improvement. Further, if the thickness of the metal wiring portion is less than 10 μm, the thermal contraction of the resin film 43 is significant, and the warpage after the solder reflow process tends to be large. The length is preferably 10 μm or more. On the other hand, when the thickness of the metal wiring portion is 50 μm or less, sufficient flexibility of the wiring substrate can be maintained, and a decrease in handling property due to an increase in weight can be prevented. The thickness of the metal wiring portion 44 can be measured by the same method as the resin film 43.

(Insulating protective film)
The insulating protective film 45 mainly improves the migration resistance of the flexible wiring board 41. The insulating protective film 45 covers the entire surface of the metal wiring portion 44 excluding the connecting portion for mounting the LED element 42 and substantially the entire surface of the resin film 43 where the metal wiring portion 44 is not formed. It is formed in an aspect.

  The insulating protective film 45 is preferably made of a cured product of a thermosetting resin composition containing a thermosetting resin. As the thermosetting resin composition, a known thermosetting resin composition can be suitably used as long as the thermosetting temperature is about 100 ° C. or less. Specifically, a thermosetting resin composition having a polyester resin, an epoxy resin, an epoxy resin and a phenol resin, an epoxy acrylate resin, a silicone resin or the like as a base resin can be preferably used. Among these, a thermosetting resin composition containing a polyester-based resin is particularly preferable as a material for forming the insulating protective film 45, from the viewpoint of excellent flexibility.

  The thermosetting resin composition for forming the insulating protective film 45 may be, for example, a white thermosetting resin composition further containing an inorganic white pigment such as titanium dioxide. By whitening the insulating protective film 45, the design can be improved. Also, the function of the reflective layer can be imparted to the insulating protective film 45.

  The formation of the insulating protective film 45 using the insulating thermosetting resin composition can be performed by a known method such as screen printing.

  The film thickness of the insulating protective film 45 is preferably 10 μm or more and 100 μm or less. If the film thickness of the insulating protective film 45 is less than 10 μm, there is a possibility that the insulating property may be lowered, and if it exceeds 100 μm, bleeding when forming the insulating protective layer by screen printing or shrinkage upon heat curing There is a possibility that warpage or the like of the wiring board due to may significantly occur. The film thickness of the insulating protective film 45 is obtained by photographing the cross section of the insulating protective film 45 using a scanning electron microscope (SEM), and measuring the film thickness of the insulating protective film 45 at 20 points in the image of the cross section. , The arithmetic mean value of the film thickness of the 20 places.

(Reflective layer)
The reflective layer 46 has high reflectivity mainly to light in the visible light wavelength range of wavelengths of 380 nm to 780 nm. The reflective layer 46 is stacked on the surface 41 A of the flexible wiring board 41 so as to cover the area excluding the LED element mounting area for the purpose of improving the light emitting capability of the LED surface light source device 20. In this embodiment, the reflective layer 46 insulates so as to surround the LED element 42 and to expose the inner peripheral edge of the area of the insulating protective film 45 removed by the LED element mounting area in plan view. It is laminated on the protective film 45. Further, the present invention is not limited to this. For example, the inner peripheral edge of the region of the insulating protective film 45 removed by the LED element mounting region is not exposed, and the inner peripheral edge of both the insulating protective film 45 and the reflective layer 46 is It may be laminated so as to match and make the same shape.

  The reflective layer 46 is not particularly limited as long as it is a member having a reflective surface for reflecting light from the LED element 42 and guiding it in a predetermined direction, but a foam type white polyester, white polyethylene resin, silver deposited polyester, etc. Can be used as appropriate depending on the application of the final product and its required specifications and the like.

  The film thickness of the reflective layer 46 is preferably 50 μm or more and 1 mm or less. If the film thickness of the reflective layer 46 is less than 50 μm, the desired reflectance may not be obtained, and the reflective layer is too thin, so it becomes difficult to set at a predetermined position, and if it exceeds 1 mm While it becomes cost, there exists a possibility that thickness reduction of a surface light source device can not be achieved. The film thickness of the reflective layer 46 can be measured by the same method as the film thickness of the insulating protective film 45.

(Adhesive layer)
As the adhesive layer 47, a known resin-based adhesive can be used as appropriate. Among these resin-based adhesives, urethane-based, polycarbonate-based or epoxy-based adhesives can be particularly preferably used. The adhesive layer 47 remains on the resin film 43 after the etching process of the metal wiring portion 44.

(Solder layer)
The solder layer 48 is for electrically and mechanically bonding the metal wiring portion 44 and the LED element 42. The bonding method using the solder layer 48 can be roughly divided into a reflow method and a laser method, but any of these methods can be used.

  When bonding the metal wiring portion and the LED element by soldering, a large amount of heat is applied to the resin film and the metal wiring portion, and therefore, the resin film and the metal wiring portion are different from the difference in linear expansion coefficient of the resin film and the metal wiring portion. There is a possibility that warpage may occur in the wiring substrate provided with In order to prevent such warpage, it is preferable to provide a metal foil on the surface of the resin film 43 opposite to the surface on the metal wiring portion 44 side. Further, by providing such a metal foil, the heat of the LED mounting substrate 40 at the time of lighting can also be dissipated to the casing main body 35 more.

<< LED device >>
The LED element 42 is a light emitting element using light emission at a PN junction where a P-type semiconductor and an N-type semiconductor are joined. As the LED element, a structure in which a P-type electrode and an N-type electrode are provided on the upper and lower surfaces of the element and a structure in which both a P-type and an N-type electrode are provided on one surface of the element are known. An LED element can also be used for the LED surface light source device 20. However, among the above, an LED element having a structure in which both P-type and N-type electrodes are provided on one side of the element can be particularly preferably used.

The LED elements 42 are arranged in a matrix on the flexible wiring board 41. In the present specification, "matrix-like" means a state in which the two-dimensional arrangement is made in a matrix-like manner. In the present embodiment, the LED elements 42 are arranged in a matrix, but the arrangement state of the LED elements is not particularly limited. For example, the LED elements may be arranged in a zigzag. A plurality of LED elements 42 are mounted on the flexible wiring board 41. The number of LED elements 42 mounted on the flexible wiring board 41 is not particularly limited as long as it is plural. The arrangement density of the LED elements 42 is preferably 0.02 pieces / cm ² or more and 2.0 pieces / cm ² or less, preferably 0.1 pieces / cm ² or more and 1.5 pieces / cm ² or less More preferable.

<< First Optical Sheet >>
The first optical sheet 50 is a sheet having an optical function. As a 1st optical sheet, a light transmissive reflective sheet etc. are mentioned, for example. The first optical sheet 50 shown in FIGS. 1 and 2 is a light transmitting and reflecting sheet. The light transmitting / reflecting sheet has a transmitting portion for transmitting light and a reflecting portion for reflecting light, and transmits light at a certain portion and reflects light at the other portion, thereby making the light from the LED element in a plane. And have the function of improving the in-plane uniformity of the luminance.

  The first optical sheet 50 is disposed to face the plurality of LED elements 42 in the LED mounting substrate 40, and the first optical sheet 50 is attached to the LED mounting substrate 40 by the first spacer 60. Are separated. The first optical sheet 50 is disposed substantially in parallel with the LED mounting substrate 40. That is, since the LED mounting substrate 40 is curved along the inner bottom surface 32C of the housing 30, the first optical sheet 50 is also curved such that the surface 50A is concave.

  It is preferable that the distance d1 from the surface 41A of the flexible wiring board 41 shown in FIG. 3 to the first optical sheet 50 be 0.6 mm or more and 6 mm or less. The “distance from the surface of the wiring substrate to the first optical sheet” in this specification means that a reflective layer is provided on the insulating protective layer as in the flexible wiring substrate 41, and the surface of the reflective layer is the wiring substrate. When it is a surface, it means the distance from the surface of the reflective layer to the surface of the first optical sheet on the wiring substrate side, and the insulating protective layer of the wiring substrate also has the function of a reflective layer, When the surface of the insulating protective layer is the surface of the wiring substrate, it means the distance from the surface of the insulating protective layer to the surface of the first optical sheet on the wiring substrate side. In addition, the surface on the side of the wiring substrate in the first optical sheet is the surface on the side of the wiring substrate in the resin film when the surface on the side of the wiring substrate in the first optical sheet is composed of only the surface of the resin film. However, as in the first optical sheet 50, when the reflective layer 55 is formed closer to the flexible wiring board 41 than the resin film 54, the surface of the reflective layer 55 on the flexible wiring board 41 side is used. .

  The thickness of the first optical sheet 50 is preferably 25 μm or more and 1 mm or less. If the thickness of the light transmitting and reflecting sheet is less than 25 μm, a desired reflectance may not be obtained, and if it exceeds 1 mm, the surface light source device may not be thinned. The thickness of the first optical sheet 50 is the thickness of the reflecting portion 53 described later, and the thickness of any ten points using a thickness measuring device (product name “Digimatic indicator IDF-130”, manufactured by Mitutoyo) It can obtain | require by measuring and calculating the average value. As shown in FIG. 4, the first optical sheet 50 is provided with a plurality of divided areas 51 in a plan view.

<Division area>
It is preferable that the division area 51 be divided in accordance with the number of LED elements 42. In FIG. 4, corresponding to the LED elements (4 vertical × 6 horizontal = 24), 4 vertical × 6 horizontal = 24 divided areas 51 are formed. Although the boundary line is described by a dotted line in FIG. 4, no boundary line is actually formed, and the boundary line is a virtual line, and the divided area 51 is also a virtual area.

  As shown in FIG. 4, each divided region 51 includes a plurality of transmitting portions 52 transmitting a part of light from the LED element 42 and a plurality of reflecting portions 53 reflecting a portion of light from the LED element 42. It consists of The transmitting unit 52 and the reflecting unit 53 are configured in a predetermined pattern. The portion corresponding to the LED element in each divided region is the portion to which the largest amount of light is incident, so if light is transmitted from this portion, the brightness of this portion will be higher than the brightness of the other portions of the divided region The in-plane uniformity of the luminance may be reduced. For this reason, it is preferable that the part corresponding to the LED element 42 in each division area 51 is comprised from the reflection part 53. FIG. In FIG. 4, the transmitting portion 52 is formally shown in white, and the reflecting portion 53 is shown in gray. Further, the patterns of the transmitting portion 52 and the reflecting portion 53 in each divided region 51 are the same, but they do not necessarily have to be the same and may be different patterns depending on the divided region. The transmitting part 52 and the reflecting part 53 may be a grid pattern.

  Since the first optical sheet 50 is disposed such that the central portion 51A of each divided region 51 corresponds to each LED element 42 as shown in FIG. 4, the first optical sheet 50 is closer to the central portion than the outer edge 51B. The amount of light incident on 51A increases. For this reason, in each divided region 51, it is preferable that the aperture ratio, which is the area ratio of the transmission portion 52, be gradually increased from the central portion 51A toward the outer edge portion 51B. By gradually increasing the aperture ratio in each divided region 51 from the central portion 51A toward the outer edge portion 51B, it is possible to further improve the uniformity of the luminance on the light emitting surface while securing a sufficient amount of light. The “aperture ratio” of the sectioned area in the present specification means each mass when the sectioned area of one section is divided into square cells having an equal area equally divided by about 25 to 100 equally. It means the area ratio of the transmission part in the eye. The way of defining the squares of this equal area in one sectioned area is arbitrary, but it is desirable to set, for example, the number of transmission parts 52 present in each square to be approximately equal. In addition, “aperture ratio” defines a plurality of concentric circles centered on the center point of one sectioned region at equal intervals from the central region to the outer region located outside the central region, and the circumference and circle of each concentric circle It may be determined by calculating the area ratio of the transmission part in each region between the circumference in the same manner as described above. According to this calculation method, the above-mentioned "aperture ratio" can be defined also for partition areas other than the general opening arrangement in which rectangular openings are arranged in a lattice. In each divided region 51, the aperture ratio may be gradually increased from the central portion 51A toward the outer edge portion 51B. For example, the aperture ratio is constant in a limited partial range near the central portion or the outer edge portion An area may exist.

  In the central portion 51A of each divided region 51, the area ratio is preferably reflecting portion> transparent portion, and from the viewpoint of improving the in-plane uniformity of luminance, the central portion 51A of each divided region 51 is reflected It is more preferable to comprise only the part 53. Further, in the outer edge portion 51B of each divided region 51, it is preferable that the area ratio be transmission portion> reflection portion. Specifically, the area ratio of the transmission portion 52 in the outer edge portion 51B is preferably 50% or more and 100% or less. The lower limit of the area ratio of the transmission portion 52 in the outer edge portion 51B is more preferably 60% or more, and preferably 70% or more. In addition, by forming the reflecting portion 53 in an island shape at the outer edge portion 51B, the area ratio of the transmitting portion can be theoretically made 100%. This is a configuration that can not be achieved by the conventional light transmission and reflection sheet of the punching-aperture type. As described above, in the case where the transmission section 52 and the reflection section 53 of the first optical sheet 50 are patterned by the printing method, the patterning flexibility can be expanded.

  As shown in FIG. 3, the first optical sheet 50 is composed of a resin film 54 and a reflective layer 55 laminated on part of at least one surface of the resin film 54. The reflective layer 55 can be formed by screen printing or the like. In this case, in the first optical sheet 50, the area where the reflective layer 55 exists becomes the reflective part 53, and the area where the reflective layer 55 does not exist becomes the transmissive part 52.

<Transparent part>
The transmitting portion 52 is a region in which the reflective layer 55 is not formed on any of both surfaces of the resin film 54, and is a region in which both surfaces of the resin film 54 in FIG. 3 are exposed. As the resin film 54, a conventionally known transparent film is preferably used, and the total light transmittance is preferably 85% or more. The total light transmittance can be measured using a haze meter (product name “HM-150”, manufactured by Murakami Color Research Laboratory) in accordance with JIS K-7361: 1997. The total light transmittance is an arithmetic mean of the values obtained by measuring three times.

  Examples of the resin film 54 include polyethylene terephthalate (PET) and polyethylene naphthalate (PEN). The thickness of the resin film 54 is preferably 12 μm or more and 1 mm (1000 μm) or less. The thickness of the resin film 54 can be measured by the same method as the thickness of the resin film 43.

<Reflection part>
The reflective portion 53 is a region where the reflective layer 55 in the first optical sheet 50 in FIG. 3 is present. Although the reflection part 53 shown by FIG. 3 is formed in the surface at the side of the LED element 42 of the resin film 54, it is not limited to this, it is formed in the surface on the opposite side to the surface at the side of the LED element 42 It may also be formed on both sides of the resin film 54. The film thickness of the reflective layer 55 is preferably 20 μm or more and 200 μm or less. The film thickness of the reflective layer 55 can be measured by the same method as the film thickness of the insulating protective film 45.

  The reflective portion 53 preferably has a reflectance of at least 80% or more in a visible light wavelength region of 420 nm or more and 780 nm or less. The reflectance of the reflection part formed in a narrow range like the reflection part 53 in the first optical sheet 50 is obtained by using a microspectrophotometer (product name “USPM-RU III, manufactured by Olympus”) , Can be measured accurately. The value of reflectance is a value obtained by measuring relative reflectance with barium sulfate as a standard plate and 100% of the standard plate. In addition, let a reflectance be an arithmetic mean value of the value obtained by measuring 3 times.

  The reflective layer 55 can be composed of a cured product of a thermosetting resin composition containing a white pigment such as titanium oxide. The content of the white pigment in the reflective layer 55 is preferably 10% by mass or more and 85% by mass or less in the reflective layer.

  As a thermosetting resin in the thermosetting resin composition which comprises the reflection layer 55, the combination of a conventionally well-known urethane resin and an isocyanate compound, the combination of an epoxy resin, a polyamine, and an acid anhydride, a silicone resin and a crosslinking agent Two-component thermosetting resins containing a main agent and a curing agent, as well as three-component thermosetting resins containing a curing accelerator such as amine, imidazole or phosphorus, as mentioned in combination with Be Specifically, as a thermosetting resin, the silicone-type thermosetting resin described in Unexamined-Japanese-Patent No. 2014-129549 is mentioned. The reflective layer 55 can be formed by pattern-printing the thermosetting resin composition on the surface of the resin film 54 using, for example, a printing method such as screen printing. In addition, said thickness and a reflectance are sum total thickness of the thickness of both surfaces, when the reflection layer is formed on both surfaces of a resin film, and is a reflectance at the time of forming a reflection layer on both surfaces.

  As described above, the first optical sheet 50 shown in FIG. 3 is composed of the resin film 54 and the reflective layer 55 laminated on a part of at least one surface of the resin film 54, In the first optical sheet, as shown in FIG. 5, for example, a plurality of openings 135 penetrating in the thickness direction of the light reflective sheet 134 are formed in the light reflective sheet 134 such as foamed polyethylene terephthalate (PET). It may be the first optical sheet 130. Similar to the first optical sheet 50, the first optical sheet 130 includes a divided area 131, a transmitting portion 132, and a reflecting portion 133. The sectioned area 131, the transmitting section 132, and the reflecting section 133 in the first optical sheet 130 are the same as the sectioned area 51, the transmitting section 52, and the reflecting section 53 in the first optical sheet 50, so It shall be omitted. Also in each of the divided regions 131 of the first optical sheet 130, the aperture ratio, which is the area ratio of the transmitting portion 132, gradually increases from the central portion 131A of the divided region 131 toward the outer edge 131B of the divided region 131. Is preferred. In the case of the first optical sheet 130, the opening 135 functions as a transmitting portion 132 that transmits light, and a portion other than the opening 135 in the first optical sheet 130 functions as a reflecting portion 133 that reflects light. . The openings 135 have an arbitrary shape (for example, a circular shape or a rectangular shape), and are distributed so as not to be connected to each other along a predetermined pattern. The opening portion 135 can be formed by press punching, punching by an engraving blade, or the like. Since press punching is excellent in running cost and productivity, it is an effective manufacturing method in mass production.

<< First Spacer >>
The first spacer 60 is for separating the first optical sheet 50 from the LED mounting substrate 40. The first spacer 60 has a function of holding the distance d1 from the surface 41A of the flexible wiring board 41 to the first optical sheet 50 at a predetermined distance, for example, 0.6 mm or more and 6 mm or less.

  The first spacer 60, as shown in FIG. 6, divides two or more openings 61 penetrating in a first direction FD, which is the thickness direction of the first spacer 60, and the openings 61, and at least A wall 62 surrounding the periphery of one opening 61, and a second surface extending along the first surface 62A so as to protrude from the first surface 62A located in the first direction FD in the wall 62 and to be separated from each other. A plurality of columnar parts 63 aligned in the direction SD are provided.

  The first spacer 60 is curved along the LED mounting substrate 40. Specifically, the first spacer 60 has a predetermined curvature such that the second surface 62 B opposite to the first surface 62 A of the wall 62 is concave and extends along the LED mounting substrate 40. It curves between the 1st outer edge 62C and the 2nd outer edge 62D which are located in the 2nd direction SD side in wall 62 by radius. The second outer edge 62C is an outer edge located on the second direction SD side and opposite to the first outer edge 62D. The “predetermined radius of curvature” in the present specification is appropriately adjusted in consideration of the radius of curvature of the inner bottom surface of the bottom, but the radius of curvature of the first spacer is set, for example, in the range of 300 mm or more and 1200 mm or less You may Although the first spacer 60 is curved in the LED surface light source device 20, the first spacer 60 is not curved as described later before being incorporated into the LED surface light source device 20. .

  The thickness t1 of the first spacer 60 shown in FIG. 3 is preferably 0.5 mm or more and 5 mm or less. If the thickness of the first spacer is less than 0.5 mm, the distance between the LED element and the first optical sheet is too short, so each section of the first optical sheet in a plan view of the first optical sheet The central portion of the region may be brighter than the outer edge, and if it exceeds 5 mm, the surface light source device may not be thinned. In the present specification, “the thickness of the first spacer” means the side opposite to the bottom surface of the first spacer from the bottom surface of the first spacer in the direction perpendicular to the bottom surface of the first spacer on the wiring substrate side. It means the distance to the upper surface which is the surface of The thickness t1 of the first spacer 60 is an arithmetic mean value of values obtained by randomly measuring the thickness of the first spacer 60 at ten places.

  The first spacer 60 and the flexible wiring board 41 are fixed. It does not specifically limit as a fixing method of the 1st spacer 60 and the flexible wiring board 41, The fixing by adhesion | attachment or a mechanical fixing means is mentioned. "Adhesion" in the present specification is a concept including "stickiness". In FIG. 3, the first spacer 60 and the flexible wiring board 41 are fixed via the double-sided adhesive tape 111. Specifically, the bottom surface 60A of the first spacer 60 (the second surface 62B of the wall portion 62 described later) and the reflective layer 46 of the flexible wiring board 41 are fixed by being bonded via the double-sided tape 111. ing. By fixing the first spacer 60 and the flexible wiring board 41, positional deviation of the first spacer 60 with respect to the LED element 42 can be suppressed. The first spacer 60 and the flexible wiring substrate 41 may be fixed not by the double-sided tape 111 but by using an adhesive or a pressure-sensitive adhesive. Although the first spacer 60 is fixed to the reflective layer 46 in FIG. 3, the first spacer 60 may be formed by forming a through hole in the reflective layer of the wiring substrate or by not providing the reflective layer on the wiring substrate. The first spacer may be fixed to the insulating protective film, and the through hole is formed in the reflective layer and the insulating protective layer of the wiring substrate, or the reflective layer and the insulating protective layer are not provided on the wiring substrate. Thus, the first spacer may be fixed to the metal wiring portion.

  The first spacer 60 and the first optical sheet 50 are fixed. The fixing method of the first spacer 60 and the first optical sheet 50 is not particularly limited, and fixing by adhesion or mechanical fixing means may be mentioned. In FIG. 3, the first spacer 60 and the first optical sheet 50 are fixed by being adhered via the double-sided tape 112. Specifically, the upper surface 60B of the first spacer 60 (the tip end surface of the columnar portion 63 described later) and the first optical sheet 50 are bonded via the double-sided adhesive tape 112. By fixing the first spacer 60 and the first optical sheet 50, positional deviation of the first optical sheet 50 with respect to the first spacer 60 and the LED element 42 can be further suppressed. The first spacer 60 and the first optical sheet 50 may be fixed using an adhesive or an adhesive instead of the double-sided tape 112.

  The material constituting the first spacer is not particularly limited, but it is easy to mold and is made of resin (first resin) from the viewpoint of protecting the first optical sheet 50 and the like from impact. preferable. Among the first resins, white resins are preferable from the viewpoint of guiding the light to the first optical sheet 50 by increasing the reflectance. The first spacer 60 preferably further includes particles in addition to the resin from the viewpoint of improving light diffusion. Moreover, since not only visible light but also ultraviolet light is emitted from the LED element 42, there is a possibility that members in the LED surface light source device 20 may be deteriorated by ultraviolet light. For this reason, it is preferable that the first spacer 60 further includes an ultraviolet absorber in addition to the resin in order to suppress the ultraviolet deterioration.

  The Young's modulus at 25 ° C. of the first resin is preferably 0.5 GPa or more and 5 GPa or less. If the Young's modulus of the first resin is less than 0.5 GPa, there is a possibility that the strength for fixing the wiring substrate or the first optical sheet can not be secured in the wall portion, and if it exceeds 5 GPa There is a possibility that the spacer of can not be curved with a predetermined radius of curvature. The lower limit of the Young's modulus at 25 ° C. of the first resin is more preferably 1 GPa or more, and the upper limit is more preferably 4 GPa or less.

  Examples of the first resin include polycarbonate resin, acrylonitrile-butadiene-styrene copolymer resin (ABS resin), acrylonitrile-styrene-acrylate copolymer resin (ASA resin), acrylonitrile-butadiene-styrene copolymer resin (AES resin), Polymethyl methacrylate resin (PMMA resin), polyacetal resin, polyvinyl chloride resin, polyethylene resin, polypropylene resin, polyethylene terephthalate resin, or a mixture of two or more of these resins can be mentioned. Among these, polycarbonate resins, ABS resins, ASA resins, ASA resins, AES resins, PMMA resins, polyacetal resins, or a mixture of two or more of these resins is preferable from the viewpoint of heat resistance and moldability.

Examples of the particles include inorganic particles. Examples of the inorganic particles include inorganic oxide particles such as silica, alumina, titania (TiO ₂ ), tin oxide, antimony-doped tin oxide (ATO), and zinc oxide fine particles. The particles are preferably contained in the first spacer 60 at a ratio of 10 parts by mass to 250 parts by mass with respect to 100 parts by mass of the first resin.

  It does not specifically limit as said ultraviolet absorber, A triazine type ultraviolet absorber and a benzotriazole type ultraviolet absorber are mentioned. Among these, triazine-based ultraviolet absorbers are preferable from the viewpoint of not absorbing light in the visible light region as much as possible, and capable of efficiently absorbing ultraviolet light and hardly causing yellowing even when used for a long period of time. As a commercial item of a triazine series ultraviolet absorber, BASF Corporation TINUVIN 1577 ED is mentioned, for example. Moreover, you may add a hindered amine light stabilizer etc. as needed.

The first spacer 60 preferably has antistatic properties. If dust adheres during manufacture or use of the surface light source device, it may cause a failure, but dust may adhere during manufacture or use of the surface light source device because the first spacer 60 has antistatic properties. It can be suppressed. Since the antistatic property can be expressed by the surface resistance value, when the first spacer 60 has the antistatic property, the surface resistance value of the first spacer 60 is 10 ¹² Ω / □ or less. Is preferred. The surface resistance value can be measured using a resistivity meter (product name “Hiresta-UP MCP-HT450”, manufactured by Mitsubishi Chemical Analytech Co., Ltd., probe: URS) in accordance with JIS K 6911: 2006. The surface resistance value of the first spacer 60 is obtained by randomly measuring the surface resistance value of the wall 62 at 10 points, and taking the measured surface resistance value of 10 points as an arithmetic mean value. As a method of imparting antistatic properties to the first spacer 60, a method of coating a composition containing an antistatic agent by spraying or immersion may be mentioned.

  The glass transition temperature (Tg) of the first spacer 60 is preferably over 85 ° C. In the case where the surface light source device is incorporated into a vehicle such as a car, the first spacer 60 is heated by the engine or the like, so that the environment test of leaving the first spacer 60 at 85 ° C. for 1000 hours is performed. Even if there is, it is required not to flow. If the glass transition temperature of the first spacer 60 exceeds 85 ° C., the first spacer 60 may be left in an environment at 85 ° C. for 1000 hours even if it is subjected to an environmental test. The flow of the spacer 60 can be suppressed. Moreover, since heat more than an environmental test may be added in summer, when the summer is considered, it is more preferable that the glass transition temperature of the 1st spacer 60 exceeds 115 degreeC. Here, since the surface light source device is very thin, the distance between the first optical sheet and the LED mounting substrate is very precisely designed, and temporarily the first spacer flows. If this is done, the distance between the first optical sheet and the LED mounting substrate changes, so that uneven brightness occurs, and the in-plane uniformity of the brightness decreases. From this, the heat resistance reliability of the first spacer 60 is very important. The glass transition temperature of the first spacer 60 is obtained by scraping 10 mg of the first spacer 60 into a sample, and using a differential scanning calorimeter (DSC), it is measured at a temperature rising rate of 5 ° C./min. The glass transition temperature of the first spacer 60 is an arithmetic mean value of the values measured three times. When two or more glass transition temperatures of the first spacer 60 are confirmed, the lowest glass transition temperature is adopted as the glass transition temperature.

  The molding shrinkage of the first spacer 60 is preferably less than 1.0%. If the molding shrinkage ratio of the first spacer 60 is less than 1.0%, it is possible to suppress the dimensional change of the first spacer 60, the occurrence of warpage, and the like during cooling after molding. The measurement of the molding shrinkage of the first spacer 60 is carried out according to JIS K 6911: 1995, but in the measurement of the molding shrinkage of the first spacer 60, the first spacer 60 is heated to It is assumed that a molded product obtained by melting the resin constituting the spacer 60 of 1 and pouring the resin into a mold and solidifying it.

  The method of manufacturing the first spacer 60 is not particularly limited, but the first spacer 60 can be obtained by, for example, a three-dimensional printer, cutting, injection molding, or the like.

<Aperture>
The openings 61 are for transmitting the light from the respective LED elements 42. The number of the openings 61 is not particularly limited, but in FIG. 6, 4 vertical × 6 horizontal = 24 openings corresponding to the number of LED elements 42 (4 vertical × 6 horizontal = 24) The portion 61 is formed.

  Since each opening 61 is for transmitting the light from each LED element 42, each opening 61 has a size such that the LED element 42 enters the opening 61 when the first spacer 60 is viewed in plan. It has become. In FIG. 7, one LED element 42 is disposed in one opening 61, but a plurality of LED elements may be disposed in one opening.

  Although the openings 61 shown in FIG. 7 are all the same size, the openings 61 need not be the same size and may be of different sizes.

<Wall part>
In the wall portion 62, the first surface 62A is convex and the second surface 62B is concave. By curving the first spacer 60 so that the second surface 62B is concave, the inner bottom surface 32C can correspond to the convex housing 30 as well.

  The wall 62 partitions the openings 61 and surrounds the periphery of the at least one opening 61 as described above. The wall 62 preferably surrounds the periphery of the two or more openings 61, and more preferably surrounds the periphery of all the openings 61. The wall portions 62 shown in FIG. 6 are in the form of a lattice and surround the periphery of all the openings 61. In the present specification, “lattice-like” means a structure in which a plurality of openings are arranged in a matrix by a wall in a plan view of the first spacer. Examples of the shape of the opening in plan view of the first spacer include a polygonal shape such as a quadrilateral shape, an elliptical shape, and a circular shape. Examples of the square shape include a square shape, a rectangular shape, and a rhombus shape. In the first spacer 60 shown in FIG. 6, rectangular openings 61 are arranged in a matrix by the wall 62.

  In addition, the corner on the opening side of the wall may be curved in a plan view of the first spacer. The corner portion is curved in plan view of the first spacer, so that the wall portion is less likely to be broken even when vibration or impact is applied to the wall portion, and the number of reflections at the corner portion Can be reduced, so that the reduction in luminance can be suppressed.

  The thickness of the wall portion 62 is preferably 0.5 mm or more and 10 mm or less. If the thickness of the wall 62 is 0.5 mm or more, the first optical sheet 50 can reliably function as a support, and if 10 mm or less, the opening diameter of the opening 61 is sufficient. Therefore, the reduction in luminance can be suppressed. In the present specification, "the thickness of the wall" means the thickness of the thinnest part of the wall.

  The thickness of the wall 62 may be uniform throughout, but the thickness of a part of the wall 62 may be thicker than the thickness of the other part. Specifically, the thickness of the first outer edge 62C and the second outer edge 62D in the wall 62 causes the first spacer 60 to curve between the first outer edge 62C and the second outer edge 62D. Between the first outer edge 62C and the second outer edge 62D if the width of the other part (for example, the part along the second direction SD) in the wall 62 is too large. The thickness of the first outer edge 62C and the second outer edge 62D of the wall 62 is different from that of the other portion of the wall (for example, a portion along the second direction SD). It may be larger than the thickness of.

  When the thickness of the wall 62 is uniform throughout, the ratio of the thickness of the wall to the thickness of the first spacer (the thickness of the wall / the thickness of the first spacer) is 0.04 or more and 0.99 or less Is preferred. If this ratio is 0.04 or more, the strength of the wall 62 can be maintained. If the ratio is 0.99 or less, it is easy to bend. The thickness of the first spacer 60 and the thickness of the wall portion 62 are randomly measured at ten places, and are taken as the arithmetic mean value of the measured ten places. However, when the thickness of the first spacer 60 differs depending on the portion, the thickness of the first spacer 60 is measured at the thinnest portion of the first spacer 60.

(Frame part)
The frame portion 64 has a rectangular shape in plan view, but the shape of the frame portion can be appropriately changed in accordance with the shape of the LED mounting substrate and the like. The frame portion 64 has substantially the same size as the flexible wiring board 41.

(Partial division)
The partition part 65 partitions between the openings 61. The partition 65 shown in FIG. 6 is preferably provided integrally with the frame 64. By integrally forming the partition portion 65 with the frame portion 64, it is possible to obtain a first spacer having no joint, and therefore, it is possible to perform the process of assembling the surface light source device more than forming the first spacer from a plurality of members. It is possible to simplify and reduce the risk of misalignment of the first optical sheet in the vibration test. In addition, since the first spacer does not have a joint, it is possible to reduce optical loss without light entering the joint. In the present specification, "provided integrally" means not only when there is no boundary between the frame and the partition, that is, when the frame and the partition are integrally formed, but also the partition Is a concept including the case where it is joined to the frame. In the first spacer 60, the frame portion 64 and the partition portion 65 are integrally formed. The partition 65 is preferably provided integrally with the frame 64 in order to increase the strength of the wall 62, but the partition may not be provided integrally with the frame.

  It is preferable that the partition part 65 is arrange | positioned in the position corresponding to the boundary part 51C between the division area 51, as FIG. 9 shows. In the present specification, “a boundary between divided regions” means a portion including a region assumed to be a boundary between divided regions from the pattern of the transmitting portion and the reflecting portion. FIG. 9 is a plan view of the first spacer 60 and the first optical sheet 50 from the LED element 42 side.

  As shown in FIG. 3, the opening diameter of the opening 61 increases from the bottom surface 60A to the upper surface 60B in the thickness direction of the first spacer 60 in the side surface 62E facing the opening 61 of the wall 62 So it is inclined. By forming the wall portion 62 having such a side surface 62E, it is possible to reflect the light emitted from the LED element 42 by the side surface 62E of the wall portion 62 and to guide it to the first optical sheet 50. Light can be emitted from the light source device 20 more efficiently. The side surface 62E may have a curved shape in the cross section in the thickness direction of the first spacer 60, but preferably has a linear shape from the viewpoint of ease of fabrication. Also, the wall may be inclined such that the diameter of the opening increases from the top surface to the bottom surface of the first spacer.

  The side surface 62E of the wall 62 is preferably a rough surface. Specifically, for example, the arithmetic average roughness Ra of the side surface 62E is preferably 0.1 μm to 100 μm. If Ra of the side surface 62E is 0.1 μm or more, diffuse reflection is increased, so the in-plane uniformity of luminance can be further improved, and if it is 100 μm or less, the number of reflections does not increase too much. It can suppress that the frequency which 1 spacer 60 absorbs light increases, and can suppress the fall of the in-plane uniformity of brightness | luminance. Ra can be measured using a surface roughness measuring device (product name “SE-3400”, manufactured by Kosaka Laboratory Ltd.) in accordance with JIS B0601: 1999. Ra is randomly measured at 10 points, and is taken as the arithmetic mean value of 10 points of measured Ra. The method for roughening the side surface 62E is not particularly limited, and examples thereof include a method in which the wall portion 62 contains particles described later or a sand blast method.

  Although the frame portion 64 and the partition portion 65 are integrally provided in the wall portion 62, the frame portion 64 and the partition portion 65 may not be integrally provided. That is, the frame and the partition may be separately manufactured, and the partition may be disposed inside the frame to obtain the wall. Moreover, two or more wall parts may be joined together to obtain a wall part.

<Pillar part>
As shown in FIGS. 6 and 7, a plurality of columnar portions 63 are provided so as to protrude from the first surface 62A of the wall portion 62 and to be spaced apart from each other and to be aligned in the second direction SD. As shown in FIG. 6, the columnar portion 63 is provided at the corner 64A of the frame 64, the intersection 64B of the frame 64 with the partition 65, and the intersection 65B of the partition pieces 65A. Although the arrangement position of the columnar portion 63 is not particularly limited, for example, as shown in FIG. 10A, the columnar portion 63 is not the corner portion 64A of the frame portion 64 and the partition portion 65. It may be provided in any part 64C other than the crossing part 64B, and as shown in FIG. 10 (B), provided in any part 65C other than the crossing part 65B of the partition pieces 65A constituting the partitioning part 65. It may be done.

  The first spacer 60 is curved between the first outer edge 62C and the second outer edge 62D located on the second direction SD side with a predetermined radius of curvature, but in this state, the second spacer 60 In the direction SD, as shown in FIG. 7, in the adjacent columnar portions 63, the distance d3 between the tip portions 63A is equal to or larger than the distance d4 between the root portions 63B (distance d3 距離 distance d4). In the present specification, “the distance between the tip portions” means that, when the width of the tip portion is substantially constant or spreads to the tip surface, from the end on the other adjacent pillar portion side in the tip surface of one pillar portion. The distance to the end on the side of the one columnar portion in the end surface of the other columnar portion is taken as the distance between the centers of the end surface when the width of the end portion narrows toward the end surface. In FIG. 7, since the width of the tip 63A is substantially constant, the distance d3 between the tips 63A is the distance from the end 63D on the other columnar portion 63 side of the tip surface 63C of one columnar portion 63. The distance from the end 63D on the side of one columnar portion 63 to the end surface 63C of the other columnar portion 63 is set. In addition, “the distance between root portions” means the one end at the root portion of one columnar portion adjacent to the other columnar portion side (intersection with the first surface) to the root portion of the other columnar portion. The distance to the end on the columnar part side (the point of intersection with the first surface) is taken. In FIG. 7, the distance d4 between the root portions 63B is the one columnar portion in the root portion 63B of one columnar portion 63 from the end 63E on the other columnar portion 63 side to the root portion 63B of the other columnar portion 63. It is the distance to the end 63E on the 63 side.

  In the second direction SD, it is preferable that the angle of each columnar portion 63 with respect to the first direction FD (the angle of each columnar portion 63 with respect to the dotted line N in FIG. 7) be substantially equal. Since the angle is substantially equal from the first outer edge 62C to the second outer edge 62D of the wall 62, light can be guided to the viewer along the first direction FD. In the present specification, "the angles of the columnar portions with respect to the first direction are substantially equal" means that the difference between the maximum value and the minimum value of the angles is within 5 °. In FIG. 7, since each columnar portion 63 extends along the first direction FD, the angle of each columnar portion 63 with respect to the first direction FD is approximately 0 °.

  In FIG. 7, in the second direction SD, the lengths L of the columnar parts 63 are all substantially equal. Since all the lengths L of the columnar parts 63 are substantially equal, all the distances between the LED element 42 and the first optical sheet 50 can be equal in the second direction SD. In the present specification, “the length of the columnar portion” means the distance from the first surface in the extending direction of the columnar portion to the tip of the columnar portion. Specifically, in FIG. 7, the length L of the columnar portion 63 is the distance from the first surface 62A in the extending direction TD of the columnar portion 63 to the tip of the columnar portion 63. Moreover, "all the lengths of the columnar parts are almost equal" means that the difference between the maximum value and the minimum value of the lengths is within 0.2 mm.

  In FIG. 7, in the second direction SD, the height H of the columnar portion 63 gradually decreases from the central portion 62F of the wall portion 62 to the first outer edge 62C and the second outer edge 62D. The front end surfaces 63C of the plurality of columnar portions 63 constitute a support surface for supporting the first optical sheet 50, but the height H of the columnar portions 63 is set to the first outer edge from the central portion 62F of the wall portion 62. By gradually lowering the portion 62C and the second outer edge 62D, a convex support surface can be formed. The “height of the columnar portion” in the present specification is a virtual one including a point which is orthogonal to the first direction and which is the most protruded on the side opposite to the first surface side in the second surface of the wall portion. It means the distance from the plane to the tip of the column. Specifically, in FIG. 7, the height H of the columnar portion 63 is orthogonal to the first direction FD, and on the opposite side to the first surface 62A side of the second surface 62B of the wall portion 62. It is the distance from the virtual plane P including the most projecting point 62G to the tip of the columnar part 63.

  As described above, the first spacer 60 shown in FIG. 7 is in a state after bending, but in the state before bending, as shown in FIG. 8, the first surface 62A of the wall 62 and the second surface The surface 62B is flat, and the distance d3 between the tip portions 63A of the adjacent columnar portions 63 is smaller than the distance d4 between the root portions 63B of the columnar portions 63 in the second direction SD (see FIG. Distance d4> distance d3). Before the bending, the distance d3 and the distance d4 of the adjacent columnar parts 63 satisfy the above relationship, and the first spacer 60 is curved with a predetermined curvature radius so that the second surface 62B becomes concave. When this is done, the angles of the columnar parts 63 with respect to the first direction FD can be made substantially equal, so that light can be guided to the observer side along the first direction FD.

  Further, in the state before bending, as shown in FIG. 8, in the second direction SD, the angle θ of the columnar portion 63 with respect to the first surface 62A is the first outer edge from the central portion 62F of the wall 62 It is preferable that the diameter gradually decreases to 62C and the second outer edge 62D. By setting the angle θ as such, when the first spacer 60 is curved with a predetermined curvature radius so that the second surface 62B is concaved, the angle of the columnar portion 63 with respect to the first direction FD θ can be made approximately equal. When the first spacer 60 is curved at a predetermined radius of curvature, the angle θ is such that the size of the first spacer 60 and the columnar portion 63 are substantially equal to the angle of the columnar portion 63 with respect to the first direction FD. Is appropriately designed in consideration of the number of

  Even in the state before bending, the lengths L of the columnar parts 63 are substantially equal in the second direction SD, but the height H of the columnar parts 63 is the second direction as shown in FIG. In SD, the height gradually decreases from the central portion 62F of the wall 62 to the first outer edge 62C and the second outer edge 62D. Thus, the lengths L of the columnar portions 63 are made approximately equal, and the height H of the columnar portions 63 is gradually lowered from the central portion 62F of the wall portion 62 to the first outer edge 62C and the second outer edge 62D. Thus, when the first spacer 60 is curved with a predetermined curvature radius so that the second surface 62B is concaved, the height H of the columnar portion 63 is set to the first from the central portion 62F of the wall portion 62. Since the outer edge 62C and the second outer edge 62D can be gradually lowered, a convex support surface can be formed.

  The shape of the columnar portion 63 is not particularly limited. For example, in addition to the prismatic shape as shown in FIG. 6, a cylindrical shape (see FIG. 11A), a pyramidal shape (see FIG. 11B), and a conical shape (Refer to FIG. 11 (C)), A truncated pyramid (refer to FIG. 11 (D)), A truncated cone (Refer to FIG. 11 (E)), A substantially conical shape with a curved tip (refer to FIG. 11 (F)) Etc. When the columnar portion 63 is in the shape of a prism, a column, a truncated pyramid, a truncated cone, or a substantially conical shape having a curved tip, it is possible to suppress a crack in the tip. On the other hand, if the columnar part 63 has a pyramid shape, a cone shape, a truncated pyramid shape, a truncated cone shape, or a substantially conical shape with a curved tip, the distance d3 between the tip portions 63A is the distance between the root portions 63B. Easy to make d4 or more. The columnar portion 63 shown in FIG. 6 has a square pole shape. Further, although the tip end surface 63C of the columnar portion 63 shown in FIG. 6 is a flat surface, the tip end of the columnar portion 63 as shown in FIG. 12 so as to support the first optical sheet 50 smoothly. The surface 63C may be cut or the like to have a shape conforming to a predetermined curvature.

  The ratio of the length L of the columnar part 63 to the thickness of the first spacer 60 (the length of the columnar part / the thickness of the first spacer) is preferably 0.009 or more and 0.96 or less. If this ratio is 0.009 or more, it can be easily bent, and if it is 0.96 or less, the strength of the first spacer 60 can be maintained. The thickness of the first spacer 60 and the length L of the columnar portion 63 are randomly measured at ten places, and are taken as the arithmetic mean value of the measured ten places. However, if the thickness of the first spacer and the length of the columnar part differ depending on the part, the thickness of the first spacer and the length of the columnar part shall be measured at the shortest part of the columnar part. Do. The width of the columnar portion 63 is preferably equal to or less than the width of the frame portion 64 or the partition portion 65 from the viewpoint of suppressing blocking of the light from the LED element 42.

  Alignment of the first optical sheet with respect to the LED element may be performed by the columnar section 63. In this case, a hole is provided in the first optical sheet, and by inserting the columnar portion into the hole, positioning of the first optical sheet with respect to the LED element is facilitated, and vibration is applied. Even in this case, positional deviation of the first optical sheet with respect to the LED element can be further suppressed.

  When the first optical sheet 130 having a plurality of openings 135 penetrating therethrough is used as the first optical sheet, one or more of the openings 135 of the openings 135 may be used as the hole. In this case, since the opening 135 is a through hole, the hole is also a through hole. However, when a hole is provided separately from the opening 135, the hole may not be a through hole. The "hole" in the present specification is a concept including not only a through hole but also a non-through hole such as a recess. Moreover, even if it is an optical sheet which does not have the opening part which functions as a permeation | transmission part, it is applicable if it is an optical sheet which has a hole which lets a columnar part enter.

<Other First Spacer>
In the first spacer 60, the wall portion 62 is in a lattice shape, but the wall portion may not be in a lattice shape. For example, the wall portion may have the openings arranged in a staggered manner. Specifically, as in the first spacer 140 shown in FIG. 13, the wall portion 142 may be in a honeycomb shape. Similarly to the first spacer 60, the first spacer 140 shown in FIG. 13 also has two or more openings 141 penetrating the first direction FD, which is the thickness direction of the first spacer 140, The wall portion 142 partitions the openings 141 and surrounds the periphery of at least one opening portion 141, and the columnar portion 143 protrudes from the first surface 142A located in the first direction FD in the wall portion 142. And are arranged in the second direction SD along the first surface 142A so as to be separated from each other, and the second surface on the opposite side to the first surface 142A in the wall portion 142 is concaved, It curves between the 1st outer edge part 142B located in the 2nd direction SD side in the wall part 142, and the 2nd outer edge part 142C with a predetermined | prescribed radius of curvature. The first spacer 140 is the same as the first spacer 60 except that the wall portion 142 has a honeycomb shape, and thus the description thereof is omitted here. In addition, when using the LED mounting substrate 40 in which the LED elements 42 are arranged in a matrix, the first spacer 60 in which the wall portion 62 is in a grid is used, and the LED mounting in which the LED elements are arranged in a zigzag In the case of using a substrate, the first spacer 140 in which the wall portion 142 has a honeycomb shape can be used.

  The first spacer 60 includes the frame 64 and a wall 62 having a partition 65 located inside the frame 64 and partitioning the openings 61. However, the wall extends between the openings The partition is not particularly limited as long as it surrounds the periphery of at least one opening, for example, like the first spacer 150 shown in FIG. It may be in the shape of a parallel girder composed only of 154. Similarly to the first spacer 60, the first spacer 150 shown in FIG. 14 also has two or more openings 151 penetrating the first direction FD, which is the thickness direction of the first spacer 150, The wall 152 partitions the openings 151 and surrounds the periphery of the at least one opening 151, and the columnar portion 153 protrudes from the first surface 152A located in the first direction FD in the wall 152. And the second surface SD of the wall 152 opposite to the first surface 152A is arranged in a concave shape so as to be spaced apart from each other in the second direction SD along the first surface 152A. It curves between the 1st outer edge part 152B located in the 2nd direction SD side in the wall part 152, and the 2nd outer edge part 152C with a predetermined | prescribed radius of curvature. However, in FIG. 14, the wall 152 does not surround the periphery of the opening 151 present at the outermost periphery. The first spacer 150 is the same as the first spacer 60 except that the wall portion 152 is constituted only by the partition portion, and therefore the description thereof is omitted here.

  The first spacer 60 has a convex support surface formed by the tip end surface 63C of the columnar portion 63, but like the first spacers 160 and 170 shown in FIG. 15 and FIG. The support surface configured by the tip end surfaces 163C and 173C of 173 may be concave or flat. By making the support surface concave, the first spacer can be disposed along the casing whose inner bottom surface is convex, and the first optical sheet is concavely curved toward the viewer Can. Also, by making the support surface flat, the first spacer can be disposed along the casing whose inner bottom surface is convex, and the first optical sheet can be disposed flat. .

  Like the first spacer 60, the first spacers 160 and 170 respectively have two or more openings penetrating in the first direction FD, which is the thickness direction of the first spacer 60, and FIGS. As shown in the drawings, walls 162 and 172 which partition the openings and surround the periphery of at least one opening, and first surfaces 162A and 172A located in the first direction FD in the walls 162 and 172. And a plurality of columnar portions 163 and 173 aligned in a second direction SD along the first surfaces 162A and 172A so as to protrude from the first surface 162 and to be separated from each other.

  The first spacers 160 and 170 are formed in such a manner that the second surfaces 162B and 172B opposite to the first surfaces 162A and 172A in the wall portions 162 and 172 are concave and are along the LED mounting substrate. Curved between the first outer edge 162C, 172C and the second outer edge 162D, 172D located on the second direction SD side along the first surface 162A, 172A in the wall 162, 172 with a radius of curvature of ing. Although the first spacers 160 and 170 are curved as described above in the LED surface light source device, the first spacers 160 and 170 will be described later before being incorporated into the LED surface light source device. So not curved.

  Also in the first spacers 160 and 170, in the second direction SD, the distance d3 between the tip portions 163A and 173A of the adjacent columnar portions 163 and 173 is equal to or greater than the distance d4 between the root portions 163B and 173B ( Distance d3 距離 distance d4).

  Further, also in the first spacers 160 and 170, the angles of the columnar portions 163 and 173 with respect to the first direction FD in the second direction SD (the columnar portions 163 and 173 with respect to the dotted line N in FIGS. The angles) are preferably approximately equal.

  In the first spacer 60, the lengths L of the columnar portions 63 are all substantially equal in the second direction SD, but in the first spacers 160 and 170, the columnar portions in the second direction SD The length L of 163, 173 gradually increases from the central portion 162F, 172F of the wall portion 162, 172 to the first outer edge 162C, 172C and the second outer edge 162D, 172D.

  As shown in FIG. 15, in the second direction SD, the first spacer 160 has a height H of the columnar portion 163 that is equal to the first outer edge portion 162C and the second outer edge portion from the central portion 162F of the wall portion 162. It is getting higher gradually to 162D. By setting the height H of the columnar portion 63 in this manner, a concave support surface can be formed. Further, as shown in FIG. 17, in the second direction SD, the height H of the columnar portion 173 is from the first outer edge portion 172C to the second outer edge portion 172D of the wall portion 172 as shown in FIG. It is almost equal. By setting the height H of the columnar portion 173 in this manner, a flat support surface can be formed.

  As described above, the first spacers 160 and 170 shown in FIGS. 15 and 17 are in the state after bending, but in the state before bending, the wall portion 162 as shown in FIGS. The first surfaces 162A and 172A and the second surfaces 162B and 172B of the 172 are flat surfaces, and in the second direction SD, the distance d3 between the tip portions 163A and 173A of the adjacent columnar portions 163 and 173 is The distance d4 between the root portions 163B and 173B of the columnar portions 163 and 174 is smaller than the distance d4 (distance d4> distance d3). When the distance d3 and the distance d4 of the first spacers 160 and 170 satisfy the above relationship, the first spacers 160 and 170 are curved with a predetermined radius of curvature, respectively, in the first direction FD. Since the angles of the columnar portions 163 and 173 can be made substantially equal, light can be guided to the viewer side along the first direction FD.

  In the state before bending, in the second direction SD, the angle θ of the columnar portions 163 and 173 with respect to the first surfaces 162A and 172A is the first outer edge portion from the central portions 162F and 172F of the wall portions 162 and 172. It is preferable that the diameter gradually decreases to 162C, 172C and the second outer edge portions 162D, 172D.

  In the state before the bending shown in FIG. 16, in the second direction SD, the length L of the columnar portion 163 extends from the central portion 162F to the first outer edge 162C and the second outer edge 162D in the same manner as after the bending. Although the length H gradually increases, the height H of the columnar portion 163 gradually increases from the central portion 162F to the first outer edge portion 162C and the second outer edge portion 162D in the second direction SD. Thus, the second surface 162B becomes concave by gradually increasing the height H of the columnar portion 163 from the center portion 162F of the wall portion 162 to the first outer edge portion 162C and the second outer edge portion 162D. As described above, when the first spacer 160 is curved with a predetermined radius of curvature, the height H of the columnar portion 163 is gradually increased from the central portion 162F of the wall portion 162 to the first outer edge portion 162C and the second outer edge portion 162D. The concave support surface can be formed. Further, in the state before the bending shown in FIG. 18, the length L of the columnar portion 173 in the second direction SD is the same as that after the bending from the central portion 172F of the wall portion 172 to the first outer edge portion 172C and The length L of the columnar portion 173 of the central portion 172F of the first spacer 170 and the columnar portions of the first outer edge 172C and the second outer edge 172D gradually increase toward the second outer edge 172D. The difference with the length L of 173 is smaller in the first spacer 170 than in the first spacer 160. For this reason, when the first spacer 170 is curved with a predetermined radius of curvature so that the second surface 172B is concave, the height H of the columnar portion 173 can be made substantially equal, so that the flat shape is formed. Support surface can be formed.

  In the above, although the curving first spacer 60 is curved when incorporated into the LED surface light source device 20 or the LED image display device 10, the first spacer in a curved state is changed to the LED surface light source device or LED You may incorporate in an image display apparatus.

  The first spacer 180 shown in FIGS. 19 and 20 is manufactured in a curved state. For this reason, unlike the first spacer 60, it is curved even when no load is applied.

  Like the first spacer 60, as shown in FIG. 19, the first spacer 180 has two or more openings 181 penetrating in the first direction FD, which is the thickness direction of the first spacer 180, and A wall 182 which divides the openings 181 and surrounds the periphery of the at least one opening 181, and protrudes from the first surface 182A located in the first direction FD in the wall 182 and is separated from each other And a plurality of columnar portions 183 aligned in the second direction SD along the one surface 182A. Also, the first spacer 180 is curved between the first outer edge 182C and the second outer edge 182D located on the second direction SD side of the wall 162 with a predetermined radius of curvature in the manufacturing state. In the second direction SD, the distance d3 between the end portions 183A of adjacent columnar portions 183 is equal to or larger than the distance d4 between root portions 183B of adjacent columnar portions 183 (d3 d d4). The other configuration of the first spacer 180 is also similar to that of the first spacer 60 after bending, and thus the description thereof is omitted here.

  The support surface of the first spacer 180 is convex, but may be concave or flat as described above. When the support surface of the first spacer 180 is concave or flat, the first spacer 180 has the same shape as the first spacers 160 and 170 after bending, so the description is omitted here. It shall be.

<< Second Optical Sheet >>
The second optical sheet 70 is a sheet having an optical function. The second optical sheet is not particularly limited as long as it is a sheet having an optical function, and examples thereof include a light diffusion sheet, a lens sheet, and a reflective polarization separation sheet. The second optical sheet 70 shown in FIGS. 1 and 2 is a light diffusion sheet. By arranging the second optical sheet 70 which is a light diffusion sheet, the light transmitted through the first optical sheet 50 can be further diffused by the second optical sheet 70, and the in-plane uniformity of the luminance is further increased. It can be improved. When the second optical sheet is a lens sheet, the lens sheet 90 may not be provided, and when the second optical sheet is a reflective polarization separation sheet, a reflective polarization separation sheet 100 may not be provided. When a lens sheet or a reflective polarization separation sheet is used as the second optical sheet, the same one as the lens sheet 90 or the reflective polarization separation sheet 100 can be used.

  The second optical sheet 70 is disposed on the light emitting side of the first optical sheet 50. The second optical sheet 70 is separated from the first optical sheet 50 by the second spacer 80. The second optical sheet 70 is disposed substantially in parallel with the first optical sheet 50. That is, since the first optical sheet is curved so that the back surface is concave and the surface is convex, the second optical sheet 50 is also curved so that the back is concave and the surface is convex. doing.

  The distance d2 from the first optical sheet 50 to the second optical sheet 70 shown in FIG. 3 is preferably 0.5 mm or more and 5 mm or less. If the distance from the first optical sheet 50 to the second optical sheet 70 is less than 0.5 mm, the light diffusion function may not be sufficiently exhibited. If the distance exceeds 5 mm, the surface light source device may be thinned. May not be able to In the present specification, “the distance from the first optical sheet to the second optical sheet” means the first optical sheet side of the second optical sheet from the surface of the first optical sheet side of the second optical sheet Shall mean the distance to the plane of The distance from the first optical sheet 50 to the second optical sheet 70 is an arithmetic mean value of values obtained by randomly measuring this distance at 10 points.

  The distance (OD) from the surface 41A of the flexible wiring board 41 to the second optical sheet 70 is preferably 1 mm or more and 10 mm or less from the viewpoint of thinning the LED surface light source device 20. The “distance from the surface of the wiring substrate to the second optical sheet” in this specification means the distance from the surface of the wiring substrate to the surface of the second optical sheet on the wiring substrate side. The distance from the surface 41A of the flexible wiring board 41 to the second optical sheet 70 is an arithmetic mean value of values obtained by randomly measuring 10 points of this distance. The upper limit of the distance from the surface 41A of the flexible wiring board 41 to the second optical sheet 70 is preferably 5 mm or less.

  The thickness of the second optical sheet 70 is preferably larger than the thickness of the first optical sheet 50. Since the thickness of the second optical sheet 70 is larger than the thickness of the first optical sheet 50, the second optical sheet 70 is more difficult to bend than the first optical sheet 50. Therefore, the second optical sheet 70 can maintain the distance between the first optical sheet 50 and the second optical sheet 70 at a predetermined distance by the frame-shaped second spacer 80.

  The thickness of the second optical sheet 70 is preferably 0.3 mm or more and 5 mm or less. If the thickness of the second optical sheet 70 is less than 0.3 mm, the light diffusion effect may not be sufficiently obtained. If the thickness exceeds 5 mm, the surface light source device can be thinned. It may not be possible. The thickness of the second optical sheet 70 can be measured by the same method as the thickness of the first optical sheet 50.

  The second optical sheet 70 is preferably made of resin. In the present specification, "made of a resin" means that the resin is a main component. The second optical sheet 70 is, for example, a minute and random for exhibiting a light diffusing function, which is formed on one surface side of a semitransparent resin film made of polycarbonate resin, acrylic resin or the like, and the resin film. And a lens layer having a lens array and the like.

<< Second Spacer >>
The second spacer 80 is for separating the second optical sheet 70 from the first optical sheet 50. In addition, the second spacer 80 holds the distance d2 from the first optical sheet 50 to the second optical sheet 70 at a predetermined distance, for example, 0.5 mm or more and 5 mm or less, and the surface 41A of the flexible wiring board 41 And the second optical sheet 70 at a predetermined distance, for example, 1 mm or more and 10 mm or less.

  The second spacer 80 is curved along the inner bottom surface 32 </ b> C of the housing 30. Specifically, the second spacer 80 is curved such that the top surface 80A on the second optical sheet 70 side is concave and the bottom surface 80B on the inner bottom surface 32C of the housing 30 is concave.

  The thickness t 2 of the second spacer 80 shown in FIG. 3 is larger than the thickness t 1 of the first spacer 60. The thickness t2 of the second spacer 80 is preferably 1 mm or more and 10 mm or less. If the thickness of the second spacer is less than 1 mm, the distance between the first optical sheet and the second optical sheet is too short, so in plan view of the second optical sheet, the second optical sheet There is a possibility that the part corresponding to the central part of each divided area may be brighter than the part corresponding to the outer edge, and if it exceeds 10 mm, there is a possibility that the surface light source device can not be thinned. In the present specification, “the thickness of the second spacer” refers to the top surface of the second spacer from the bottom surface of the second spacer in the direction perpendicular to the bottom surface which is the surface on the inner bottom side of the housing in the second spacer It shall mean the distance to The thickness h2 of the second spacer 80 is an arithmetic mean value of values obtained by randomly measuring the thickness of the second spacer 80 at ten places.

  The second spacer 80 has a frame shape as shown in FIG. In the “frame shape” in the present specification, not only a configuration in which there is no gap but one round connection, there may be gaps in the middle as long as they are almost connected. The second spacer 80 shown in FIG. 21 is provided with a gap 80C for connection with a terminal or the like. The second spacer 80 has one opening 81 and is disposed so as to surround the outer peripheral surface of the first optical sheet 50 and the outer peripheral surface of the first spacer 60. The second spacer 80 is disposed so as to surround not only the outer peripheral surface of the first optical sheet 50 and the outer peripheral surface of the first spacer 60 but also the outer peripheral surface of the flexible wiring board 41 as shown in FIG. ing. That is, the LED mounting substrate 40, the first optical sheet 50, and the first spacer 60 are located inside the second spacer 80. Since the second spacer 80 is shaped like a frame, light transmitted through the first optical sheet 50 and directed to the second spacer 80 side is reflected by the second spacer 80, and the second optical It can be led to the seat 70. In addition, by forming the second spacer 80 in a frame shape, the contact area with the second optical sheet 70 can be increased as compared to the case where the second spacer is formed of a plurality of columnar bodies. Therefore, when the LED surface light source device 20 is used, the heat of the second optical sheet 70 can be further dissipated through the second spacer 80. Further, since the second spacer 80 has a frame shape, adhesion between the second spacer 80 and the second optical sheet 70 is more than in the case where the second spacer is formed of a plurality of columnar bodies. Since the area can be increased, the second optical sheet 70 is less likely to be misaligned.

  As shown in FIG. 3, the bottom surface 80 </ b> B of the second spacer 80 is preferably in contact with the inner bottom surface 32 </ b> C of the housing 30. In the present specification, "the second surface of the second spacer is in contact with the inner bottom surface of the housing" means that the second surface of the second spacer is in direct contact with the inner bottom surface of the housing Not limited to the above, there may be a case where a substantially negligible layer such as double-sided tape, adhesive or adhesive is interposed between the second surface of the second spacer and the inner bottom surface of the housing, from the viewpoint of heat conduction. Is a concept that also In FIG. 3, a double-sided tape 113 described later is interposed between the bottom surface 80 </ b> B of the second spacer 80 and the inner bottom surface 32 </ b> C of the housing 30.

  Further, an outer side surface 80D which is an outer side surface of the second spacer 80 shown in FIG. 3 is in contact with the inner side surface of the housing 30. In the present specification, "the outer surface of the second spacer" means the surface opposite to the inner surface that defines the opening of the second spacer. Also, "the outer surface of the second spacer is in contact with the inner surface of the housing" in this specification is limited to the case where the outer surface of the second spacer is in direct contact with the inner surface of the housing Also, the concept includes a case where a substantially negligible layer such as double-sided tape, adhesive, or adhesive is interposed between the outer surface of the second spacer and the inner surface of the housing. is there. In FIG. 3, the outer side surface 80 </ b> D of the second spacer 80 is in direct contact with the inner side surface of the housing 30.

  The second spacer 80 and the housing 30 are preferably fixed from the viewpoint of further suppressing the positional deviation of the second optical sheet 70 with respect to the LED element 42. It does not specifically limit as a fixing method of the 2nd spacer 80 and the housing | casing 30, The fixing by adhesion | attachment or a mechanical fixing means is mentioned. In FIG. 3, the bottom surface 80 </ b> B of the second spacer 80 and the inner bottom surface 32 </ b> C of the housing 30 are fixed by being bonded via the double-sided adhesive tape 113. Here, since the second spacer 80 has a frame shape, the bonding area with the housing 30 can be increased compared to the case where the second spacer is formed of a plurality of columnar bodies. , Easy to fix the second spacer 80. The second spacer 80 and the housing 30 may be bonded not via the double-sided tape 113 but via an adhesive or a pressure-sensitive adhesive.

  The second spacer 80 and the second optical sheet 70 are preferably fixed. The fixing method of the second spacer 80 and the second optical sheet 70 is not particularly limited, and fixing by adhesion or mechanical fixing means can be mentioned. In FIG. 3, the upper surface 80A of the second spacer 80 and the second optical sheet 70 are fixed by being adhered via the double-sided tape 114. By fixing the second spacer 80 and the second optical sheet 70, positional deviation of the second spacer 80 with respect to the LED element 42 can be further suppressed. The second spacer 80 and the second optical sheet 70 may be fixed using an adhesive or an adhesive instead of the double-sided tape 114.

  As shown in FIG. 3, the inner side surface 80E, which is the inner side surface of the second spacer 80, increases in the diameter of the opening 81 from the inner bottom surface 32C of the housing 30 toward the second optical sheet 70. It is preferable to be inclined. By forming the second spacer 80 having such an inner side surface 80E, the light emitted from the first optical sheet 50 is reflected by the inner side surface 80E of the second spacer 80, and the second optical sheet 70 is formed. Thus, the LED surface light source device 20 can emit light more efficiently. The second spacer 80 having such an inner surface 80E can be obtained, for example, by injection molding, punching, cutting or a three-dimensional printer. The inner side surface 80E may be curved in the cross section in the thickness direction of the second spacer 80, but is preferably linear from the viewpoint of ease of fabrication.

  The material forming the second spacer 80 is not particularly limited, but it is made of resin (second resin) from the viewpoint of easy molding and protection of the second optical sheet 70 and the like from impact. Is preferred. Among the second resins, white resins are preferable from the viewpoint of increasing the reflectance and guiding light to the second optical sheet 70 more.

  The second resin constituting the second spacer 80 may be the same resin as the first resin constituting the first spacer 60, but the first spacer and the second spacer have a low Young's modulus. When it is made of resin, the rigidity of the surface light source device is lowered, so that the second resin 80 constituting the second spacer 80 at 25 ° C. can maintain the rigidity in a curved state. The rate is preferably smaller than the Young's modulus at 25 ° C. of the first resin constituting the first spacer 60. The Young's modulus at 25 ° C. of the first resin constituting the first spacer 60 and the Young's modulus at 25 ° C. of the second resin constituting the second spacer 80 are respectively dynamic viscoelasticity measuring devices (product The tensile test is conducted at 25 ° C using the name “Rheogel-E4000” (manufactured by UBM), and the stress is taken along the vertical axis, and the inclination is taken from the slope of the straight part of the stress-strain curve taken along the horizontal axis. . In addition, let the said Young's modulus be an arithmetic mean value of the value obtained by measuring 3 times.

<< Lens sheet >>
The lens sheet 90 has a function of changing the traveling direction of the incident light and emitting the light from the light output side. The lens sheet 90 has a function to intensively improve the brightness in the front direction by changing the traveling direction of light having a large incident angle such as L1 and emitting the light from the light output side as shown in FIG. For example, it has a function (retroreflection function) of reflecting light having a small incident angle such as L2 and returning it to the second optical sheet 70 side, as well as the optical function.

  The lens sheet 90 is laminated along the second optical sheet 70 on the light emitting side of the optical sheet 70. That is, since the second optical sheet 70 is curved so that the surface is concave and the back is convex, the lens sheet is also curved so that the surface is concave and the back is convex. doing.

  The lens sheet 90 includes a resin film 91 and a lens layer 92 provided on one surface of the resin film 91, as shown in FIG. The lens sheet 90 is disposed so that the lens layer 92 is positioned closer to the reflective polarization splitting sheet 100 than the resin film 91.

(Resin film)
As a constituent material of the resin film 91, for example, polyester (for example, polyethylene terephthalate, polyethylene naphthalate), cellulose triacetate, cellulose diacetate, cellulose acetate butyrate, polyamide, polyimide, polyether sulfone, polysulfone, polypropylene, polymethyl Thermoplastic resins such as pentene, polyvinyl chloride, polyvinyl acetal, polyether ketone, polymethyl methacrylate, polycarbonate, or polyurethane can be mentioned.

(Lens layer)
The lens layer 92 includes a plurality of unit lenses 92A arranged side by side on the light output side. The unit lens 92A may have a triangular prism shape, or may have a wave shape or a bowl shape such as a hemispherical shape. Specifically, a unit prism, a unit cylindrical lens, a unit micro lens etc. are mentioned as a unit lens. In addition, as a lens sheet which has such a unit lens shape, a prism sheet, a lenticular lens sheet, a microlens sheet etc. are mentioned.

  The unit lens 92A preferably has an apex angle θ of 80 ° to 100 °, and more preferably about 90 °, from the viewpoint of improving the utilization efficiency of light.

<< reflection type polarization separation sheet >>
Of the light emitted from the lens sheet 90, the reflective polarization separation sheet 100 transmits only a first linear polarization component (for example, P polarization), and a second straight line orthogonal to the first linear polarization component. It has a function of reflecting a polarized light component (for example, S-polarized light) without absorbing it. The second linearly polarized light component reflected by the reflection type polarization separation sheet 100 is reflected again and depolarized (in a state including both the first linearly polarized light component and the second linearly polarized light component), Again, the light is incident on the reflective polarization separation sheet 100.

  The reflective polarization separation sheet 100 is laminated along the lens sheet on the light emission side of the lens sheet. That is, since the lens sheet is curved so that the back surface is convex and the surface is concave, the reflective polarization separation sheet is also curved so that the back is convex and the surface is concave. .

  As the reflective polarization separation sheet 100, "VIKUITI (registered trademark) DBEF (Dual Brightness Enhancement Film)" available from 3M can be used. In addition to the “DBEF”, a high brightness polarizing sheet “WRPS” available from Shinwha Intertek, a wire grid polarizer, or the like can be used as the reflective polarizing separation sheet 100.

  In addition, since the support surface of the first spacer 60 is concave, the first optical sheet 50, the second optical sheet 70, the second spacer 80, the lens sheet 90, the reflection type polarization separation sheet 100 And the first optical sheet, the second optical sheet, and the second optical sheet, when the first surface of the first spacer is convex or flat. The surfaces of the spacer, the lens sheet, and the reflective polarization separation sheet may be convex or flat.

  According to the present embodiment, in the first spacer 60, since the columnar portion 63 protrudes from the first surface 62A of the wall portion 62, it is not necessary to arrange one by one like the columnar spacer. For this reason, it is excellent in handling property. In addition, since the first spacer 60 includes the wall portion 62 which partitions the openings 61 and surrounds the periphery of the at least one opening 61, the first spacer 60 is superior in strength to the columnar spacer. The first spacers 140, 150, 160, 170, 180 also have excellent handling properties and strength for the same reason as the first spacer 60.

  According to the present embodiment, the first spacer 60 can be curved so that the second surface 62B is concave in the second direction SD, so that the inner bottom surface 32C is convex. Even if the bottom 32 of the housing 30 is curved, the first spacer 60 can be disposed along the shape of the inner bottom surface 32C of the bottom 32. Thereby, it can respond also to case 30 which has bottom 32 in which inner bottom 32C curved in concave shape. For the same reason as the first spacer 60, the first spacers 140, 150, 160, and 170 can also correspond to the housing 30 having the bottom 32 with the inner bottom surface 32C convexly curved. In addition, since the first spacer 180 is pre-curved with a predetermined radius of curvature, the first inner face 32C can also correspond to the housing 30 having the convexly curved bottom portion 32 simply by arranging without being bent. it can.

  According to the present embodiment, in a state where the first spacer is curved, in the second direction, the distance between the tips of the adjacent columnar portions is less than the distance between the root portions of the columnar portions. Since the distance between the tip end portions is smaller than that between the root portions, light may be blocked from the LED elements by the columnar portions. On the other hand, according to the present embodiment, when the first spacer 60 is curved between the first outer edge 62C and the second outer edge 62D, adjacent columnar portions 63 in the second direction SD. Since the distance d3 between the end portions 63A of the light emitting diode 63 is equal to or larger than the distance d4 between the root portions 63B of the columnar portions 63, it is possible to suppress the light from the LED elements 42 from being blocked by the columnar portions 63. Thereby, the fall of the utilization efficiency of the light from the LED element 42 in the curved state can be suppressed. The first spacers 140, 150, 160, 170, and 180 can also suppress the decrease in light utilization efficiency for the same reason as the first spacer 60.

  According to the present embodiment, since the first spacer 60 includes the wall portion 62, the first spacer 60 has higher rigidity than a columnar spacer or a simple frame-like spacer. For this reason, when a vibration test is performed on the LED surface light source device 20, the swing width of the first optical sheet 50 is smaller than in the case where a columnar spacer or a simple frame-like spacer is used. Thereby, when a vibration test is performed, position shift of the 1st optical sheet 50 with respect to the LED element 42 can be suppressed. In addition, since the first spacer 60 is higher in rigidity than a columnar spacer or a simple frame-like spacer, the first spacer 60 is less likely to be damaged even when a vibration test is performed.

  In the case where the first optical sheet is a light transmitting / reflecting sheet, the light transmitting / reflecting sheet has a pattern of a transmitting portion and a reflecting portion in each sectioned area, so positional deviation of the light transmitting / reflecting sheet occurs. Since the position of the light transmitting / reflecting sheet with respect to the LED element changes, the in-plane uniformity of the luminance may be reduced. On the other hand, in the present embodiment, since the positional deviation of the first optical sheet 50 with respect to the LED element 42 can be suppressed, the in-plane uniformity of the luminance can be improved.

  Applications of the LED image display device 10 and the LED surface light source device 20 of the present embodiment are not particularly limited, but can be used for television applications, in-vehicle applications, and advertising media applications such as billboards, for example. Among these, since the LED image display device 10 and the LED surface light source device 20 are excellent in strength, they can be suitably used for on-vehicle applications.

DESCRIPTION OF SYMBOLS 10 ... Image display apparatus 20 ... Surface light source device 30 ... Casing 32 ... Bottom part 32C ... Inner bottom face 40 ... LED mounting board 41 ... Wiring board 42 ... LED element 50, 130 ... 1st optical sheet 51, 131 ... Division area 51A 131A ... central part 51B, 131B ... outer edge part 52, 132 ... transmission part 53, 133 ... reflection part 60, 140, 150, 160, 170, 180 ... first spacer 61 ... opening 62, 142, 152, 162 , 172, 182 ... wall portions 62A, 142A, 152A, 162A, 172A, 182A ... first surfaces 62B, 162B, 172B, 182B ... second surfaces 62C, 142B, 152B, 162C, 172C, 182C ... first Outer edges 62D, 142C, 153C, 162D, 172D, 182D ... second outer edges 62F, 162F, 172F, 18 F central part 63, 143, 153, 163, 172 columnar part 63A, 163A, 173A, 183A tip part 63B, 163B, 173B, 183B root part 64 frame part 65 partition part 70 second optical Sheet 80: Second spacer

Claims (15)

It is used for a LED surface light source device provided with a flexible printed circuit board, an LED mounting board provided with a plurality of LED elements mounted on one side of the flexible printed circuit board, and an optical sheet disposed on the LED element side, A bendable spacer disposed between the LED mounting substrate and the optical sheet,
Two or more openings penetrating in a first direction which is a thickness direction of the spacer;
A wall between the openings and surrounding at least one of the openings;
And a plurality of columnar portions juxtaposed in a second direction along the first surface so as to protrude from a first surface located in the first direction in the wall portion and to be separated from each other,
The spacer is positioned on the second direction side of the wall at a predetermined radius of curvature such that a second surface of the wall opposite to the first surface is concave. When the second outer edge portion is curved between the first outer edge portion and the second outer edge portion located on the second direction side of the wall portion and opposite to the first outer edge portion; A spacer, wherein in the direction, the distance between the end portions of adjacent ones of the columnar portions is equal to or greater than the distance between the root portions of the adjacent ones of the columnar portions.   2. The spacer according to claim 1, wherein in the second direction before the bending, the distance between the tips of adjacent ones of the columnar parts is smaller than the distance between the roots of the adjacent ones of the columnar parts.   Before bending, in the second direction, the lengths of the pillars are substantially equal, and the height of each pillar is from the center of the wall to the first outer edge and the second The spacer according to claim 1, wherein the spacer gradually lowers toward the outer edge of the spacer.   Before bending, in the second direction, the length of each of the pillars gradually increases from the center of the wall to the first outer edge and the second outer edge, and each pillar The spacer according to claim 1, wherein the height of the portion gradually increases from the central portion to the first outer edge and the second outer edge. It is used for a LED surface light source device provided with a flexible printed circuit board, an LED mounting board provided with a plurality of LED elements mounted on one side of the flexible printed circuit board, and an optical sheet disposed on the LED element side, A spacer disposed between the LED mounting substrate and the optical sheet,
Two or more openings penetrating in a first direction which is a thickness direction of the spacer;
A wall between the openings and surrounding at least one of the openings;
And a plurality of columnar portions juxtaposed in a second direction along the first surface so as to protrude from a first surface located in the first direction in the wall portion and to be separated from each other,
The spacer is positioned on the second direction side of the wall with a predetermined radius of curvature such that a second surface of the wall opposite to the first surface is concave. Curved between a second outer edge located on the second direction side of the wall and opposite to the first outer edge and the second direction In the spacer, the distance between the end portions of adjacent ones of the columnar portions is equal to or larger than the distance between root portions of the adjacent ones of the columnar portions.   The spacer according to claim 5, wherein in the second direction, the height of each of the pillars gradually decreases from the center of the wall to the first outer edge and the second outer edge. .   The spacer according to claim 5, wherein in the second direction, the height of each of the pillars gradually increases from the center of the wall to the first outer edge and the second outer edge. .   The spacer according to claim 5, wherein the heights of the columnar parts are substantially equal in the second direction.   9. A spacer according to any one of the preceding claims, wherein the spacer is comprised of a polycarbonate resin.   The spacer according to any one of claims 1 to 9, wherein the wall portion is in a lattice shape or a honeycomb shape. A housing comprising a bottom;
An LED mounting board comprising: a flexible wiring board; and a plurality of LED elements mounted on a surface of the wiring board opposite to the surface on the bottom side of the wiring board;
A first optical sheet disposed on the LED element side,
And a first spacer disposed between the LED mounting substrate and the first optical sheet,
The bottom of the housing is curved between a first edge of the bottom and a second edge opposite to the first edge such that the inner bottom surface of the bottom is convex. Yes,
The LED mounting substrate is disposed along the inner bottom surface of the bottom portion,
The first spacer is a spacer according to any one of claims 1 to 4,
In the spacer, the second surface of the wall opposite to the first surface is concave, and the wall has a predetermined curvature radius so as to be along the surface of the LED mounting substrate. An LED surface light source device curved between the first outer edge and the second outer edge of the wall. A housing comprising a bottom and an opening;
An LED mounting board comprising a plurality of LED elements disposed in the housing and mounted on a flexible wiring board and one surface of the wiring board;
A first optical sheet disposed on the LED element side,
And a first spacer disposed between the LED mounting substrate and the first optical sheet,
The bottom of the housing is curved between a first edge of the bottom and a second edge opposite to the first edge such that the inner bottom surface of the bottom is convex. Yes,
The LED mounting substrate is disposed along the inner bottom surface of the bottom portion,
The first spacer is a spacer according to any one of claims 5 to 8, and the spacer is disposed such that the second surface of the wall portion is along the surface of the LED mounting substrate. LED surface light source device.   The first optical sheet includes a plurality of divided areas in a plan view, and each of the divided areas includes a plurality of transmission parts that transmit part of light from the LED element, and the plurality of transmission areas from the LED element An aperture ratio, which is a ratio of an area ratio of the transmission part in each of the divided areas, is gradually increased from a central part of the divided area toward an outer edge of the divided area. The LED surface light source device according to claim 11 or 12. A second optical sheet disposed on the light emitting side of the first optical sheet,
A frame-shaped second spacer which is disposed so as to surround the outer peripheral surface of the first optical sheet and the outer peripheral surface of the first spacer, and which separates the second optical sheet from the first optical sheet When,
The LED surface light source device according to any one of claims 11 to 13, further comprising: The LED surface light source device according to any one of claims 11 to 14,
A display panel disposed closer to the viewer than the LED surface light source device;
An LED image display device comprising:

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