TWI782444B - Light distribution control element - Google Patents

Abstract

The present invention provides a light distribution control element for realizing a thin surface light source device capable of obtaining a substantially square light beam similar to the shape of a divided area. A square plate-shaped light distribution control element that controls the light distribution of light emitted from N light emitting elements (N is an integer greater than 1) arranged on the substrate includes: a first light emitting element facing the N light emitting elements. A main surface; a second main surface opposite to the first main surface; N diffusing elements that diffuse light incident on the first main surface from each light emitting element in a direction substantially perpendicular to the optical axis of the light emitting element At the same time, the injection from the second main surface.

Description

Light distribution control element

The invention relates to a light distribution control element, a light distribution adjustment mechanism, a reflective part, a reinforcing plate, a lighting unit, a display and a television.

The present invention relates to a light distribution control element, a light distribution adjustment mechanism, a reflective part, a reinforcing plate, a lighting unit, a display and a television set, in particular to a light distribution control element and a light distribution control element used in a lighting unit that irradiates light to a display panel from the back side. Light adjustment mechanisms, reflective components, stiffeners, lighting units, displays and televisions.

Conventionally, as a backlight of a transmissive image display device such as a liquid crystal display device, a surface light source device (illumination unit) in which a plurality of LEDs (Light Emitting Diodes) are arranged in a matrix is used.

Regarding such a surface light source device, a thin device that uniformly irradiates a display area of a liquid crystal panel with uniform brightness has been pursued in the prior art. In addition, with the increase in the size of the liquid crystal panel and the demand for higher image quality, by controlling the light quantity of the LED one by one, the contrast of different divided areas in the same screen can be improved, or the local dimming ( Dimming control per zone) technology can also be used for practical applications. Such a surface light source device is disclosed in Patent Document 1, for example.

In addition, the surface light source device disclosed in Patent Document 2 is composed of an optical sheet module and a light source module using a plurality of LEDs as light sources. The optical sheet module includes a diffused light guide plate or a diffuser plate and a reflective sheet. While diffusing the light from the LED through the diffused light guide plate or diffuser plate, it is repeatedly reflected by the reflective sheet to illuminate the liquid crystal display device with uniform brightness. Uniform irradiation is performed.

In addition, in such a surface light source device, as the size of the liquid crystal panel increases and the demand for higher image quality is increased, by controlling the light intensity of the LEDs one by one, the contrast of different divided regions in the same screen can be increased or decreased. Power-hungry local dimming (dimming control per zone) technology is also available for practical use. Such a surface light source device is disclosed in Patent Document 3, for example.

prior art literature

Patent Document 1: Japanese Patent Laid-Open No. 2010-205698

Patent Document 2: Japanese Patent Laid-Open No. 2005-352427

Patent Document 3: Japanese Patent Laid-Open No. 2010-205698

The surface light source device of Patent Document 1 reflects light from a light source by a concave mirror and irradiates it toward a liquid crystal panel. Since the beam shape can be made into a roughly square shape similar to the shape of a divided area, it is most suitable for local dimming. However, in the configuration of Patent Document 1, the premise is that the light source is arranged on the side of the irradiated plane with respect to the concave mirror, and the distance between the light source and the concave mirror needs to be widened. Therefore, it is difficult to make the device itself thinner.

In addition, as another problem, if the optical axes of the respective light sources and the optical axes of the concave mirrors do not coincide exactly, the desired light quantity cannot be obtained in each divided area (that is, there is light quantity dispersion). This problem also occurs due to deformation of the substrate on which the light source is mounted or deformation of the concave mirror, so it is extremely important to suppress these deformations. In order to suppress the deformation of the substrate or the concave mirror, either the substrate or the concave mirror can be suppressed by thickening the thickness of the substrate or the concave mirror. However, if such a method is adopted, there is a problem that the surface light source device itself becomes thicker or heavier.

Furthermore, although the surface light source device of Patent Document 2 can uniformly irradiate the liquid crystal display device with uniform brightness, since the light from each LED is diffused and mixed with each other through the diffuser plate and the reflective sheet, it is difficult to perform local adjustment. Light.

On the other hand, the surface light source device of Patent Document 2 reflects the light from the light source with a concave mirror and irradiates it toward the liquid crystal panel. The shape of the light beam can be made into a roughly square shape similar to the shape of the divided area, so it is most suitable for local adjustment. However, since the partial illumination light emitted from a plurality of divided areas is only planarly synthesized, the influence of the brightness distribution of the LED cannot be completely eliminated, and it is difficult to obtain a substantially uniform illuminance distribution in the divided areas.

The present invention provides a light distribution control element, a light distribution adjustment mechanism, a reflection member, a reinforcing plate, a lighting unit, a display, and a television for realizing a thin surface light source device capable of obtaining a substantially square light beam similar to the shape of a divided area.

In order to achieve the above object, the present invention provides a light distribution control element, which is a square plate-shaped light distribution control element that controls the light distribution of light emitted from a light emitting element, and is characterized in that: The first main surface that is arranged; The second main surface that is the back side relative to the first main surface; and a diffusion element that changes the direction of light emitted from the light emitting element and incident on the first main surface. After being in a direction substantially perpendicular to the light emitting surface of the light emitting element, it is emitted from the second main surface.

If such a structure is adopted, since the diffusion element corresponding to each light emitting element diffuses the advancing direction of the light emitted from each light emitting element into a direction substantially perpendicular to the light emitting surface of the light emitting element, it is not only thin, but also can A beam similar in shape to the segmented area is obtained.

In addition, the first main surface has: a circular concave incident surface formed at a position corresponding to the light emitting element; and a plurality of concentric annular grooves formed so as to surround the incident surface, the The second main surface has a first emission surface formed of a conical concave surface formed at a position corresponding to the incident surface.

In addition, it is preferable to form notches at the four corners of the two main surfaces. In this way, by emitting light from the notch, the amount of light leaked from the side surface of the light distribution control element can be reduced, and the total amount of light emitted from the second main surface of the light distribution control element can be increased. Furthermore, a plurality of waveguides may be formed at the edge of the second main surface, and reflection may be performed by the wall surfaces of these waveguides. The so-called edge here refers to the side and/or four corners of the light distribution control element. In addition, it is preferable that the diffusion elements are arranged in N square-shaped regions.

Moreover, it is preferable that the said 2nd main surface is provided with the protrusion part which protrudes gradually with respect to the said 2nd main surface as it goes from a center part to a square part.

In addition, the present invention provides a light distribution adjustment mechanism arranged on the optical path of the light emitted from the light emitting element to adjust the light distribution of the light, and attached to the above light distribution control element, the light distribution adjustment mechanism has a plurality of The layer structure may have a structure such that the farther away from the light-emitting surface of the light-emitting element, the lower the transmittance becomes.

According to the present invention, since the partial illumination light emitted from a plurality of divided areas is not merely planarly synthesized, the influence of the luminance distribution of the LEDs can be eliminated, and a substantially uniform illuminance distribution can be obtained in the divided areas.

In addition, the plurality of layer structures can be formed by laminating a plurality of substantially circular sheet members or films having different radii around the optical axis of the light emitting element. In addition, several layers constituting the plurality of layer structures may be in a star-shaped polygonal shape. Furthermore, one or more openings may be formed in a part of the plurality of layer structures.

Furthermore, the present invention provides a reflective member attached to the above-mentioned light distribution control element, which includes: a first reflective surface abutting against an incident surface of the light distribution control element, and reflecting light emitted from the incident surface side. reflection; and a second reflection surface, which is opposed to some side surfaces of the light distribution control element, and reflects light emitted from the side surfaces.

With such a structure, since the light emitted from the side of the light distribution control element is reflected by the second reflective surface, it can enter again from the side of the light distribution control element, so the light leaked from the light distribution control element is reduced, and each light can be accurately controlled. The amount of light in the dimming zone.

In addition, it is preferable that at least a part of the top end of the side surface has a saw-toothed or wavy shape. In addition, it is preferable that the reflective member is formed of a metal or resin thin plate having a heat shrinkage rate of 0.5% or less. Furthermore, it is preferable that the reflectance of the said 1st reflective surface and the said 2nd reflective surface is 90% or more.

Furthermore, the present invention provides a reinforcing plate for a lighting unit comprising: a square plate-shaped substrate on which the light-emitting element is mounted on the surface; and the above-mentioned light distribution control element arranged to face the light-emitting element, The reinforcing plate is made of sheet metal having an L-shaped cross section, and is attached so as to extend from the upper surface of the substrate to the side surface.

With such a structure, since deformation of the substrate and the light distribution control element can be reliably suppressed by the reinforcing plate, misalignment between the substrate and the light distribution control element does not occur.

In addition, when there are a plurality of the light distribution control elements, it is preferable that the reinforcing plate is attached at a position over at least adjacent light distribution control elements. In addition, preferably the lighting unit There is a reflective part, which is arranged between the substrate and the light distribution control element to reflect the light from the light distribution control element, preferably, the reinforcing plate is located between the reflective part and the light distribution control element. between the substrates.

In addition, from another point of view, the irradiation unit including any one of the light distribution control element, the light distribution adjustment mechanism, the reflective member, and the reinforcing plate of the present invention is characterized in that it includes: a substrate, and N light emitting devices arranged on the substrate. A component, and the above-mentioned light distribution control component. In addition, the above-mentioned light distribution control element can also be applied to monitors and televisions attached to personal computers and the like.

As described above, according to the present invention, there is provided a light distribution control element for realizing a thin surface light source device capable of obtaining a substantially square light beam similar to the shape of the divided regions. In addition, a lighting unit, a display, and a television provided with the light distribution control element can be realized.

In addition, according to the present invention, it is possible to realize a light distribution adjustment mechanism for a lighting unit that is thin and can obtain a substantially uniform illuminance distribution in a divided area. In addition, a lighting unit, a display, and a television provided with the light distribution adjustment mechanism can be realized.

1: lighting device

10, 10A: lighting unit

100, 100A: LED unit

101, 101A: Substrate

110: LED components

120: reinforcement board

120a: through hole

200, 200A, 200B: reflective sheet

200a, 200b, 200Ba, 200Bb: through holes

201A: bottom face

201Aa: 1st reflective surface

201Ab, 201Ac: through hole

202A: side part

202Aa: second reflective surface

300, 600, 600A: Diffusion plate

302, 602: protrusion

310, 320, 610, 620: concave conical surface

311, 322a, 322b, 322c, 322d, 323, 325, 327, 328, 329, 330, 611, 613, 615, 622, 626, 641: groove part

321, 621: circular opening

324, 326, 625, 640: ladder department

331, 631, 633: concave part

400: Regulating flakes

410: 1st sheet

411, 412: opening

420: the second sheet

430: 3rd sheet

431: opening

619: protrusion

DE1, DE2, DE3, DE4: dimming area

FIG. 1 is a perspective view showing the configuration of a lighting device according to a first embodiment of the present invention.

2 is an exploded perspective view illustrating the configuration of a lighting unit included in the lighting device according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a structure of a diffuser plate of the lighting unit in FIG. 2 .

FIG. 4 is a cross-sectional view of the diffuser plate of FIG. 3 .

FIG. 5 is a diagram illustrating an arrangement relationship between a diffuser plate and an adjustment sheet of the lighting unit in FIG. 2 .

FIG. 6 is a diagram illustrating a structure of an adjustment sheet of the lighting unit of FIG. 2 .

FIG. 7 is a schematic diagram illustrating the effects of the diffusion plate and the adjustment sheet of the lighting unit included in the lighting device according to the first embodiment of the present invention.

8 is a photograph and a graph showing a luminance distribution of light emitted from a lighting unit included in the lighting device according to the first embodiment of the present invention.

9 is a diagram illustrating a configuration of a lighting unit included in a lighting device according to a second embodiment of the present invention.

10 is a photograph showing a luminance distribution of light emitted from a lighting unit included in a lighting device according to a second embodiment of the present invention.

Fig. 11 is a diagram illustrating a configuration of a lighting unit included in a lighting device according to a third embodiment of the present invention.

FIG. 12 is a diagram illustrating a structure of a diffuser plate of the lighting unit of FIG. 11 .

FIG. 13 is a cross-sectional view of the diffuser plate of FIG. 12 .

14 is a diagram illustrating a structure of a diffusion plate of a lighting unit included in a lighting device according to a fourth embodiment of the present invention.

15 is a diagram showing the luminance distribution of the lighting unit using the diffuser plate of the third embodiment and the luminance distribution of the lighting unit using the diffuser plate of the fourth embodiment.

FIG. 16 is a diagram illustrating the function and effect of the adjustment sheet 400 shown in FIG. 6 .

Fig. 17 is a diagram showing a modified example of the adjustment sheet according to the fifth embodiment of the present invention.

FIG. 18 is a modified example of the diffusion plate 300 shown in FIGS. 3 and 4 , and corresponds to FIG. 3( c ).

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code|symbol is attached|subjected to the same or corresponding part in a figure, and description is not repeated.

(first embodiment)

FIG. 1 is a perspective view showing the configuration of a lighting device 1 according to a first embodiment of the present invention. The lighting device 1 is a surface light source device arranged on the rear side of a liquid crystal panel (not shown) to irradiate light to the liquid crystal panel. The lighting device 1 is configured by arranging a plurality of lighting units 10 in a matrix according to the size of the liquid crystal panel, as shown in FIG. 1 .

FIG. 2 is an exploded perspective view illustrating the configuration of a lighting unit 10 that is a part of the lighting device 1 shown in FIG. 1 . As shown in FIG. 2 , the lighting unit 10 includes: a square plate-shaped LED unit 100 , a reflective sheet 200 disposed on the upper surface of the LED unit 100 , two diffuser plates 300 disposed on the upper surface of the reflective sheet 200 , and The adjustment sheets 400 are arranged on each diffuser plate 300 , for example, four adjustment sheets 400 are arranged for each diffuser plate 300 .

Hereinafter, in this specification, the long-side direction of the LED unit 100 is defined as the X-axis direction, the short-side direction is defined as the Y-axis direction, and the direction perpendicular to the X-axis direction and the Y-axis direction (that is, the direction of the LED element 110) is defined as the X-axis direction. Ejection direction) is defined as the Z-axis direction. In addition, the positive direction side of the Z-axis direction may be referred to as an upper side, and the negative direction side may be referred to as a bottom. Therefore, for the LED unit 100 in FIG. 2 , the side opposite to the reflective sheet 200 is called the upper surface, and the back side is called the bottom surface.

The LED unit 100 of each lighting unit 10 includes: a square plate-shaped substrate 101 formed of, for example, glass epoxy resin, a plurality of LED elements 110 mounted on the upper surface of the substrate 101, and a plurality of LED elements 110 mounted on the upper surface of the substrate 101. A reinforcing plate 120. In addition, as other implementation manners, the substrate 101 may also be an aluminum substrate or an FPC (Flexible printed circuits, flexible circuit board) or the like.

As shown in FIG. 2 , in this embodiment, for example, 4 (X-axis direction) × 2 (Y-axis direction) LED elements 110, the direction of its optical axis is consistent with the Z-axis direction, and the distance in the X-axis direction is They are mounted on the upper surface of the substrate 101 with a pitch of, for example, 30 mm and a pitch in the Y-axis direction of, for example, 30 mm. On the substrate 101, an anode pattern (anode pattern) (not shown) and a cathode pattern (cathode pattern) (not shown) for supplying power to each LED element 110 are formed, and each LED element 110 is connected to the anode pattern and the cathode pattern respectively. pattern electrical connections.

In addition, the substrate 101 is electrically connected to a driving circuit (not shown) through a wiring cable not shown, and a driving current is supplied from the driving circuit to each LED element 110 via an anode pattern and a cathode pattern. When a driving current is supplied to each LED element 110 , white light having an amount of light corresponding to the driving current is emitted from each LED element 110 along the Z-axis direction.

In addition, in the present embodiment, each LED element 110 is arranged in each divided area of local dimming, and local dimming (that is, dimming control for each divided area) can be performed through the control of the driving circuit.

The reinforcing plate 120 is a thin plate-shaped metal (for example, copper, iron, aluminum) member for suppressing deformation of the substrate 101 and the diffuser plate 300 . As shown in FIG. 2 , in this embodiment, for example, six reinforcing plates 120 are arranged in 3 x 2 columns along each long side of the substrate 101 by soldering or the like (for example, conductive adhesive (silver paste), solder, soldering/deposition, diffusion bonding, etc.) for surface mounting.

字狀还覆盖基板101的底面。另外，例如，各增強板120，還可以在與基板101的側面對應的位置的外表面的例如中央部附近，從上表面側朝向底面側，或者配置V字狀的切口，或者配置凹坑來使強度提高。 在各增強板120上設置與在基板101上形成的貫通孔(未圖示)連通的例如兩個貫通孔120a。各貫通孔120a，形成擴散板300的突起302(圖3(b)、圖3(c))可插通的大小，且配置在與各擴散板300的突起302對應的位置。 Each reinforcing plate 120 has a unique shape including an L-shaped portion in cross section, and is attached so as to cover at least the upper surface of the substrate 101 from the side surface. The cross-section of each reinforcing plate 120 can be L-shaped itself, or it can be set as

The lettering also covers the bottom surface of the substrate 101 . In addition, for example, each reinforcing plate 120 may be provided with a V-shaped notch or a pit from the upper surface side toward the bottom surface side, for example, near the center portion of the outer surface at a position corresponding to the side surface of the substrate 101. Improve strength. Each reinforcing plate 120 is provided with, for example, two through-holes 120 a communicating with through-holes (not shown) formed in the substrate 101 . Each through-hole 120a is formed in a size that allows the protrusion 302 ( FIG. 3( b ) and FIG. 3( c )) of the diffuser plate 300 to pass through, and is arranged at a position corresponding to the protrusion 302 of each diffuser plate 300 .

Moreover, the protrusion 302 of each diffuser plate 300 is inserted into the through-hole 120a, and is fixed by heat welding. In addition, as another embodiment, after applying an ultraviolet-curable adhesive or the like to each protrusion 302 , it may be further irradiated with ultraviolet rays to achieve more firm fixation with the substrate 101A.

In addition, the reinforcing plates 120 need only be arranged along the long side of the substrate 101 , and are not necessarily limited to an arrangement of 3 × 2 columns, but are preferably arranged across at least two diffuser plates 300 . According to such a structure, since the two diffuser plates 300 can be accurately positioned by the reinforcing plate 120, they can be accurately arranged on the XY plane (that is, on the substrate 101). In addition, deformation of the substrate 101 and the diffusion plate 300 can also be suppressed.

The reflective sheet 200 is a square sheet metal (for example, aluminum) or resin (for example, PET (Polyethylene terephthalate, polyethylene terephthalate)) sandwiched between the diffuser plate 300 and the substrate 101. manufactured parts. As shown in FIG. 2 , for example, eight through holes 200 a corresponding to positions of, for example, eight LED elements 110 and eight through holes 200 b through which protrusions 302 of the diffusion plate 300 pass are formed in the reflective sheet 200 .

In this way, in this embodiment, since the reflective sheet 200 is disposed between the diffuser plate 300 and the substrate 101, the light emitted from the LED element 110 is reflected by the bottom surface of the diffuser plate 300, and even if it does not directly enter the diffuser plate 300, it will Since the reflective sheet 200 reflects again toward the diffuser plate 300 and indirectly enters the diffuser plate 300 , almost all of the light emitted from the LED element 110 is emitted through the diffuser plate 300 .

The diffusion plate 300 is disposed on the optical path of light emitted from the LED elements 110 so as to cover the reflective sheet 200 , and is a rectangular plate-shaped optical element that diffuses the light emitted from each LED element 110 around the Z axis inside the diffusion plate 300 . Optical elements made of glass or resin (such as acrylic, PC (polycarbonate), etc.).

FIG. 3 is a diagram illustrating the structure of a diffuser plate 300 according to this embodiment. Fig. 3(a) is a top view, Fig. 3(b) is a left side view, and Fig. 3(c) is a bottom view. In addition, FIG. 4 is a cross-sectional view illustrating the structure of the diffuser plate 300. FIGS.

As shown in FIG. 3 , on the diffusion plate 300 of this embodiment, for example, four patterns (that is, four diffusion elements) are impositioned corresponding to, for example, four LED elements 110 to form, for example, four LED elements for dimming by local dimming. Dimming areas DE1, DE2, DE3, DE4.

In addition, as described above, in this embodiment, since eight LED elements 110 are arranged on the substrate 101, for example, two diffuser plates 300 are arranged along the X-axis direction as shown in FIG. 2 .

As shown in FIG. 3( b ) and FIG. 3( c ), cylindrical protrusions 302 protruding toward the negative side of the Z-axis are formed at the four corners of the bottom surface of each diffuser plate 300 . When the diffusion plate 300 is placed on the reflective sheet 200 , each protrusion 302 passes through the through hole 200 b of the reflective sheet 200 and the through hole 120 a of the reinforcing plate 120 , and protrudes toward the bottom side of the substrate 101 . The diffusion plate 300 is fixed to the substrate 101 by thermally welding each protrusion 302 to the bottom surface side of the substrate 101 .

As shown in FIG. 3( a ) and FIG. 4( b ), for example, four concave conical surfaces 310 are formed on the upper surface of each diffusion plate 300 corresponding to the positions of, for example, four LED elements 110 . If the light emitted from each LED element 110 passes through the diffusion plate 300 and reaches the concave conical surface 310, a part of the light passes through the concave The conical surface 310 is emitted, and at the same time other part of the light is diffused in the diffusion plate 300 around the Z axis under the action of the concave conical surface 310 . Thus, the uniformity of the diffuser plate 300 is achieved.

As shown in FIGS. 3( a ) and 3 ( b ), notches 350 are formed at the four corners of the upper surface of each diffuser plate 300 . The notch 350 emits light thereby, thereby reducing the amount of light leaked from the side surface of the diffuser plate 300 and increasing the total amount of light emitted from the upper surface of the diffuser plate 300 .

字狀、U字狀、V字狀等各種形狀。以下，關於其他槽部(槽部322a等)也是同樣的。 In addition, on the upper surface of each diffusion plate 300 , for example, two grooves 311 extending in parallel, for example, are formed inwardly from approximately the center of each side. The groove portion 311 functions as a waveguide, and when the light emitted from each LED element 110 reaches the groove portion 311 , it passes through the wall surface of the groove portion 311 and is reflected toward the upper surface of the diffuser plate 300 . Therefore, leakage of light from each of the dimming areas DE1 , DE2 , DE3 , and DE4 to the adjacent dimming areas can be suppressed. In addition, the shape of the groove portion 311 is not limited, and its cross section can be set as

Various shapes such as letter, U, and V. Hereinafter, the same applies to other groove portions (groove portion 322a and the like).

As shown in Fig. 3 (c), Fig. 4 (b), and Fig. 4 (d), on the bottom surface of each diffusion plate 300, set: for example four concave cones formed at positions corresponding to four concave conical surfaces 310 The surface 320 and the circular opening 321 connected with each concave conical surface 320 and selectively formed. The details will be described later. In this embodiment, in the space in each circular opening 321 (when the LED element 110 has a certain height, and when the circular opening 321 is not provided), each concave conical surface 320 or each concave The space inside the conical surface 320) accommodates each LED element 110.

In addition, each concave conical surface 320 becomes an incident surface on which light emitted from each LED element 110 enters, and functions as a kind of condensing lens. Therefore, generally, although the light emitted from each LED element 110 has a wide angular component (that is, has a large diffusion angle), the diffusion angle can be narrowed by being incident on each concave conical surface 320 .

As shown in Fig. 3 (c), Fig. 4 (b), and Fig. 4 (d), on the bottom surface of each diffusion plate 300, for example, four annular grooves 322a, 322b, 322c, 322d are sequentially formed to form a concentric circles to surround each concave conical surface 320 . In addition, in this embodiment, the depths of the grooves 322c and 322d deviated from the concave conical surface 320 are deeper than the grooves 322a and 322b ( FIG. 4( b ), FIG. 4( d )), and the light diffused by the concave conical surface 310 And light with a large diffusion angle emitted from the LED element 110 is reflected by the walls of the grooves 322 a , 322 b , 322 c , and 322 d to the upper surface of the diffuser plate 300 , and then emitted from the upper surface of the diffuser plate 300 .

As shown in FIG. 4( b ), a step-shaped groove 323 deeper than the groove 322 c is formed in the center of the bottom surface of each diffuser 300 , so that the adjacent dimming regions DE1 and The dimming area DE4 is distinguished, or the dimming area DE2 and the dimming area DE3 are distinguished.

Similarly, as shown in FIG. 4( d ), step-shaped grooves 325 deeper than the grooves 322c and 322d are formed approximately in the center of the bottom surface of each diffuser plate 300, thereby facing each other in the X-axis direction. The adjacent area DE1 is distinguished from the dimming area DE2, or the dimming area DE3 is distinguished from the dimming area DE4.

That is, in each dimming area, the light diffused in the lateral direction (that is, the X-Y plane) is reflected by the wall surfaces of the grooves 323 and 325 in the direction of the upper surface of the diffusion plate 300, and the light leaked to the adjacent dimming area Fewer. In addition, a plurality of stepped portions 324 are formed at both ends in the Y-axis direction of the bottom surface of each diffuser plate 300 so as to become thinner in a stepwise manner ( FIG. 4( b )), and a plurality of stepped portions 326 are formed at both ends in the X-axis direction. Stepwise thinning ( FIG. 4( d )), the light diffused in the lateral direction (that is, the X-Y plane) of each dimming area is reflected by the wall surface of the stepped part 324, 326 in the direction of the upper surface of the diffusion plate 300. The amount of light leaking outward from both sides in the Y-axis direction and both sides in the X-axis direction decreases.

As shown in FIG. 3( c ) and FIG. 4( a ), on the bottom surface of each diffuser plate 300 , for example, three grooves 327 extending inward in parallel from the central portions of both sides facing in the Y-axis direction are formed. If from each When the light emitted from the LED element 110 reaches the groove portion 327, it is reflected by the wall surface of the groove portion 327 to the direction of the upper surface of the diffuser plate 300, so that between the adjacent dimming area DE1 and the dimming area DE2 in the X-axis direction, and 1. The light leaked between the dimming area DE3 and the dimming area DE4 decreases.

As shown in FIG. 3( c ) and FIG. 4( c ), on the bottom surface of each diffuser plate 300 , for example, three grooves 328 extend inward in parallel from substantially central portions of both sides facing in the X-axis direction. When the light emitted from each LED element 110 reaches the groove portion 328, it is reflected to the upper surface direction of the diffuser plate 300 by the wall surface of the groove portion 328, so that the difference between the adjacent dimming area DE1 and the dimming area DE4 in the Y-axis direction is reduced. Between, and, between the dimming area DE2 and the dimming area DE3, the leaked light becomes less.

As shown in FIG. 3( c ) and FIG. 4( e ), at the four corners of the bottom surface of each diffuser plate 300 , for example, three grooves 329 extending in diagonal directions of the diffuser plate 300 are formed. When the light emitted from each LED element 110 reaches the groove portion 329 , it passes through the wall surface of the groove portion 329 and is reflected toward the upper surface of the diffuser plate 300 . In addition, at the central portion of the bottom surface of each diffuser plate 300 , for example, ten grooves 330 extending in the diagonal direction of the diffuser plate 300 are formed. When the light from each LED element 110 reaches the groove portion 330 , it passes through the wall surface of the groove portion 330 and is reflected toward the upper surface of the diffuser plate 300 .

As shown in FIG. 3( c ) and FIG. 4( e ), a plurality of circular recesses 331 are formed at the ends in the Y-axis direction of the bottom surface of each diffuser plate 300 . When the light from each LED element 110 reaches the concave portion 331, it is reflected toward the upper surface direction of the diffusion plate 300 by the wall surface of the concave portion 331, so even at the end of the Y-axis direction of the diffusion plate 300, the light goes toward the diffusion plate. 300 reflectors in the direction of the upper surface.

In this way, in the diffuser plate 300 of this embodiment, for example, four patterns corresponding to, for example, four LED elements 110 (that is, four diffuser elements) are impositioned, and each pattern is distinguished by the grooves 323, 325 to form, for example, four patterns. Dimming areas DE1, DE2, DE3, DE4. And, the light from each LED element 110 passes through the concave conical surfaces 310, 310 and The grooves 322 a , 322 b , 322 c , 322 d , etc. reflect in the direction of the upper surface of the diffuser plate 300 and emit from the upper surface of the diffuser plate 300 .

FIG. 18 is a modified example of the diffusion plate 300 shown in FIGS. 3 and 4 , and corresponds to FIG. 3( c ). In FIG. 18 , slit regions 340A to 340D are shown in addition to the concave conical surface 320 , the groove portion 329 , the recessed portion 331 , and the like described above.

A total of four slit regions 340A are formed in each concave conical surface 320 of the diffuser plate 300 and near each end portion of the diffuser plate 300 in the short-side direction. The slit area 340A has a plurality of deep slits parallel to the longitudinal direction of the diffuser plate 300 .

In addition, the depth of each slit can be 0.3mm~1.5mm, preferably 0.5mm~1.2mm, more preferably 0.8mm~1.0mm. Although the width of the opening of each slit depends on the relationship with the pitch between the slits, it may be about 0.05 mm to 0.5 mm. In addition, all the slits may have the same depth, or may be deeper as they deviate from the center. The shape of each slit may be any one or more of substantially V-shaped, substantially U-shaped, and angular in cross section. The conditions of the slits need only be the same in the slit regions 340B to 340D.

A total of two slit regions 340B are formed near the center of each end portion of the diffuser plate 300 in the longitudinal direction. The slit area 340B has a plurality of slits parallel to the longitudinal direction of the diffuser plate 300 .

A total of two slit regions 340C are formed between rows of concave conical surfaces 320 of the diffuser plate 300 and at positions sandwiching the center of the diffuser plate 300 . The slit area 340C has a plurality of slits parallel to the longitudinal direction of the diffuser plate 300 .

A total of two slit regions 340D are formed between rows of concave conical surfaces 320 of the diffuser plate 300 and at positions sandwiching the center of the diffuser plate 300 . The slit area 340D has a plurality of slits parallel to the short-side direction of the diffuser plate 300 .

The method of forming each slit in the slit regions 340A to 340D is not particularly limited, and may be formed by, for example, laser, etching, or mold.

Here, as described later using FIG. 9 , although the diffuser plate 300 is arranged on the reflective sheet 200 having the side portion 202A, and as shown in FIG. In some cases, light passes between the teeth of the side surface portion 202A, but in some cases, the space between the diffuser plates 300 becomes dark.

In order to prevent this, it is only necessary to change the optical path in a direction perpendicular to the surface direction of the diffuser plate 300 . In this case, it is effective to provide the slit regions 340A and 340B.

In addition, only the slit area 340A may be provided, or only the slit area 340B may be provided. In this case, it is possible to prevent darkening between the diffuser plates 300 compared to not providing any of the slit regions 340A, 340B.

However, when only one of the slit region 340A and the slit region 340B can be formed, it is preferable to form only the slit region 340B. This is because the gap between the diffuser plates 300 near the slit region 340B is easily formed larger than the gap between the diffuser plates 300 near the slit region 340A, and this is supplemented.

On the other hand, when the diffuser plate 300 becomes very large, since the pitch between the LED elements 110 becomes large, it is effective to provide the slit regions 340C and 340D in order to emit light of uniform intensity.

In addition, only the slit area 340C may be provided, or only the slit area 340D may be provided. In this case, the intensity of light from the diffuser plate 300 can be increased compared to the case where neither of the slit regions 340C and 340D is provided.

However, when only one of the slit region 340C and the slit region 340D can be formed, it is preferable to form only the slit region 340C. This is because the column pitch of the LED elements 110 corresponding to each concave conical surface 320 is larger than the row pitch, so the light intensity at the center between the columns is lower than that at the center between the rows, so this is supplemented.

FIG. 5 is an exploded perspective view illustrating the arrangement relationship between the diffuser plate 300 and the adjustment sheet 400 according to this embodiment. In addition, FIG. 6 is a diagram illustrating the structure of the adjustment sheet 400, FIG. 6(a) is a plan view, and FIG. 6(b) is an exploded perspective view.

As shown in FIG. 5 , the adjustment sheet 400 is a substantially circular sheet-shaped member, and is bonded to each concave conical surface 310 of the diffuser plate 300 in such a manner that its center approximately coincides with the center of the light emitting surface of each LED element 110. , to adjust the light distribution of the light emitted from each dimming area DE1, DE2, DE3, DE4. However, the adjustment sheet 400 of this embodiment does not have to be adhered to the diffuser plate 300 , but only needs to be fixedly arranged on the optical path of light emitted from the LED element 110 by some means.

As shown in FIG. 6 , the regulating sheet 400 of this embodiment is a first sheet 410 , a second sheet 420 , and a third sheet 430 with different radii that are sequentially laminated on a transparent film 450 by printing, vapor deposition, etc. in this order. And constituted. The transparent film 450 , the first sheet 410 , the second sheet 420 , and the third sheet 430 of this embodiment can each transmit a part of the light from the LED element 110 .

The transparent film 450 has a thickness of 2.0 μm to 10 μm and is made of, for example, PET. The first sheet 410, the second sheet 420 and the third sheet 430 are punched out of a polyurethane resin sheet with a thickness of 2.0 μm to 10 μm (for example, Victorian punching, etc.) obtained. In addition, the first sheet 410, the second sheet 420, and the third sheet 430 need only adjust light distribution (that is, transmittance), and other synthetic resins such as nylon may be used as other embodiments. The transparent film 450 is provided on the diffuser plate 300 side as long as it can connect the first sheet 410 and the like to the diffuser plate 300 For example an adhesive layer. In addition, the first sheet 410 and the like may be directly formed on the diffuser plate 300 by printing, vapor deposition, or the like, without providing the transparent film 450 .

As shown in FIG. 6( b ), the first sheet 410 is, for example, a 16-point star-shaped sheet member. Furthermore, the second sheet 420 is, for example, an octagonal star-shaped sheet member having a smaller radius than the first sheet 410 . Furthermore, the third sheet 430 is, for example, an octagonal star-shaped sheet member whose radius is smaller than that of the second sheet 420 .

The transparent film 450, the first sheet 410, the second sheet 420, and the third sheet 430 are arranged on the same axis after their respective centers are aligned. The second sheet 420 is located on the first sheet 410, and the third sheet 430 is located on the second sheet 420. above, and integrated (Figure 6(a)). In addition, in the center of the third sheet 430 of this embodiment, a circular opening 431 is formed, and for example, eight circular openings 411 arranged to surround the second sheet 420 are formed in the first sheet 410, and the arrangement There are, for example, 8 circular openings 412 outside the opening 411 .

Thus, in the adjustment sheet 400 of this embodiment, the second sheet 420 and the third sheet 430 overlap at the center (that is, the portion where the opening 431 is formed), and the first sheet 410, the second sheet 420, and the third sheet 430 overlap each other at the center. Its outside overlaps. In addition, the second sheet 420 and the third sheet 430 are overlapped on the outer side thereof, and a part where the first sheet 410 exists and a part where the first sheet 410 does not exist are formed outside the second sheet 420 (that is, where the openings 411 and 412 are formed). part).

In this way, if the overlapping degrees of the first sheet 410 , the second sheet 420 , and the third sheet 430 are different, the transmittance will be correspondingly different. In this embodiment, according to the light distribution characteristics (that is, luminance distribution) of the light from the LED element 110, the degree of overlapping of the first sheet 410, the second sheet 420, and the third sheet 430, the size and position of the openings 411 and 412 Adjustment is performed to partially change the transmittance and adjust to an approximately uniform luminance distribution as a whole.

FIG. 7 is a schematic diagram illustrating the effect of the diffusion plate 300 and the adjustment sheet 400 according to this embodiment. In addition, although only the dimming area DE1 (that is, only one diffusion element) is schematically shown in FIG. 7 for convenience of description, the same applies to the other dimming areas DE2 to DE4.

As shown in FIG. 7 , in the lighting unit 10 of the present embodiment, lights (light rays) indicated by arrows are emitted from the LED elements 110 arranged in the space in the circular opening 321 of the diffusion plate 300 .

Specifically, light having a diffusion angle of 0° to 180° relative to the central axis of the light emitting surface is emitted from the LED element 110 as indicated by arrow a. The light emitted from the LED element 110 is condensed by the lens effect of the concave conical surface 320 of the diffuser plate 300 , and is incident into the diffuser plate 300 , and enters the diffuser plate 300 .

And, when reaching the concave conical surface 310 at the front (upper in FIG. 7 ), part of the light is emitted from the concave conical surface 310 (arrow b), and the rest of the light is reflected by the concave conical surface 310 and diffused in the diffusion plate 300. (arrow c, arrow e). And, the light diffused in the diffuser plate 300 by the concave conical surface 310 enters the inside of the diffuser plate 300, passes through the wall surfaces of the grooves 322a, 322b, 322c, 322d, etc. The upper surface of 300 shoots out (arrow d).

And, a part of the light diffused by the concave conical surface 310 enters the inside of the diffuser plate 300 and exits from the side surface of the diffuser plate 300 (arrow e), but if the diffuser plate 300 is used, most of the light from the LED element 110 can be made A portion eventually shoots out from the upper surface of the diffuser plate 300 .

FIG. 8 is a photograph and a graph showing the luminance distribution of light emitted from the lighting unit 10 according to the present embodiment. In FIG. 8 , in order to explain the effects of the diffusion plate 300 and the adjustment sheet 400 of this embodiment, not only the luminance distribution ( FIG. 8( c )) but also The luminance distribution (that is, the luminance distribution of the light emitted from the LED element 110) without the diffusion plate 300 and the adjustment sheet 400 is shown ( FIG. 8( a )), and, although the diffusion plate 300 is present However, the luminance distribution (that is, the luminance distribution of light emitted from the diffuser plate 300 ) in the case where there is no sheet 400 is adjusted ( FIG. 8( b )).

In addition, each graph of FIG. 8( a ) to FIG. 8( c ) corresponds to each photograph, and shows the relative brightness of each photograph at each position from the axial direction and the Y-axis direction.

First, comparing FIG. 8(a) and FIG. 8(b), it can be seen that by using the diffuser plate 300, not only the amount of light at a position close to the LED element 110 is relatively reduced, but also the amount of light at a position away from the LED element 110 is relatively increased. Therefore, light is emitted from the entire diffuser plate 300, and the uniformity can be improved.

In addition, comparing Fig. 8(b) and Fig. 8(c), it can be seen that in this embodiment, since the regulating sheet 400 is adhered to the concave conical surface 310 of the diffusion plate 300, the light emitted from the concave conical surface 310 (Fig. 7 , the arrow b) is partially reflected by the adjusting sheet 400 , and the reflected light is emitted from a position relatively deviated from the adjusting sheet 400 . Therefore, it is possible to suppress hot spots (high-brightness portions) generated by the LED elements 110 , and to emit light with a uniform light intensity from the entire diffuser plate 300 .

In addition, since the reflective sheet 200 ( FIG. 2 and FIG. 7 ) is arranged between the diffuser plate 300 and the substrate 101 , the light emitted from the LED element 110 is reflected on the bottom surface of the diffuser plate 300 and is not directly incident on the diffuser plate 300 . In the case of the diffuser plate 300, or although it is incident on the diffuser plate 300 for a while, the light emitted from the bottom surface of the diffuser plate 300 after being reflected by the concave conical surface 310 is reflected again towards the diffuser plate 300 by the reflective sheet 200, and enters the diffuser plate 300, Thus, almost all the light emitted from the LED elements 110 is emitted from the upper surface of the diffuser plate 300 .

FIG. 16 is a diagram illustrating the function and effect of the adjustment sheet 400 according to this embodiment, and shows the luminance distribution in the X-axis direction and the Y-axis direction of light emitted from the lighting unit 10 . In FIG. 16, "α" is the brightness distribution when no adjustment sheet 400 is arranged, "β" is the brightness distribution when only the first sheet 410 is arranged, and "γ" is the brightness distribution when the first sheet 410 and the second sheet 410 are arranged. Brightness score in case of flake 420 "δ" is the luminance distribution when the first sheet 410, the second sheet 420, and the third sheet 430 are arranged.

Table 1 is a table showing the peak value of the luminance distribution (lower graph) in the X-axis direction of FIG. Graph) peak value and the table of the transmittance calculated from the peak value.

As described above, the adjustment sheet 400 of this embodiment is composed of the first sheet 410 , the second sheet 420 , and the third sheet 430 formed on the transparent film 450 . Therefore, the transmittance of the adjustment sheet 400 is low near the emission surface of the LED element 110 (i.e., the central part) (see "δ" in Table 1 and Table 2), and as it deviates from the emission surface of the LED element 110 (i.e., along the toward the peripheral part) and become higher (refer to "γ" and "β" in Table 1 and Table 2).

Therefore, the luminance distribution of the light emitted from the diffusion plate 300 of this embodiment has a peak on the emitting surface of the LED element 110 as shown by “α” in FIG. The distribution is such that this peak is suppressed, and a substantially uniform luminance distribution can be obtained in each of the dimming areas DE1, DE2, DE3, and DE4 (see "δ" in FIG. 16 ).

In addition, in this embodiment, although the three-layer structure of the first sheet 410, the second sheet 420, and the third sheet 430 is provided, it is not limited to such a structure. For example, the thickness of each film may be changed. A 2-story structure is possible, and a 4-story or more structure is also possible. That is, the adjustment sheet 400 only needs to have a multi-layer structure. This point is also the same in the case of the fifth embodiment described later.

Although the above is a description of the present embodiment, the present invention is not limited to the above-mentioned structure, and various modifications can be made within the scope of the technical idea of the present invention.

For example, in this embodiment, although the case where two diffuser plates 300 are arranged on one substrate 101 on which eight LED elements 110 are mounted has been described, it is not limited to such a structure. The substrate 101 corresponds to the size of the diffuser plate 300 .

In addition, although the diffusion plate 300 of this embodiment describes the case where four patterns (that is, four diffusion elements) are imposed corresponding to the four LED elements 110 , it is only necessary to arrange one diffusion element for each LED element 110 . Yes, the number of impositions is not limited to 4. That is, for N LED elements 110 (N is an integer greater than or equal to 1), it is only necessary to arrange N diffusion elements on the diffusion plate 300 .

(second embodiment)

FIG. 9 is a diagram illustrating a configuration of a lighting unit 10 according to a second embodiment of the present invention. FIG. 9( a ) is a diagram showing a state where the diffuser plate 300 is attached to the reflection sheet 200A, and FIG. 9( b ) is a diagram showing a state where the diffuser plate 300 and the reflection sheet 200A are disassembled.

The lighting unit of this embodiment is different from the first embodiment in that the reflective sheet 200A disposed additionally on the diffuser plate 300 is formed to surround the bottom surface and the side surfaces of the diffuser plate 300 . In addition, in FIG. 9, for convenience of description, only one diffuser plate 300 and reflective sheet 200A are shown, and other structures are omitted. However, it is also possible to double the size of the reflective sheet 200A and store, for example, two diffusers 300 in one reflective sheet 200A.

As shown in FIG. 9, the reflection sheet 200A (reflection member) of this embodiment is formed of a metal sheet (for example, aluminum) or a resin (for example, PET (Polyethylene terephthalate, polyethylene terephthalate)). Components with a reflectivity of 90% or more and a heat shrinkage rate of 0.5% or less.

The reflective sheet 200A has a general shape of a square box with an open upper surface, and the diffusion plate 300 can be housed inside. The reflection sheet 200A has a bottom surface portion 201A formed to cover the bottom surface of the diffuser plate 300 , and side portions 202A formed to cover, for example, four side surfaces of the diffuser plate 300 . In this case, the bottom surface portion 201A is in contact with the bottom surface of the diffusion plate 300 that becomes the incident surface of light. In addition, the side surface portion 202A faces the side surface of the diffuser plate 300 .

The first reflection surface 201Aa is formed on the inner surface of the bottom portion 201A, and the second reflection surface 202Aa is formed on the inner surface of the side surface portion 202A. The side portions 202A may or may not be connected to each other at short side portions. In the latter case, strictly speaking, the reflection sheet 200A is not box-shaped, but even in this case, it can be said to be a box-shape as a rough shape.

In addition, four through holes 200Aa corresponding to the positions of the LED elements 110 and four through holes 200Ab through which four protrusions 302 of the diffuser plate 300 respectively pass are formed in the bottom portion 201A of the reflective sheet 200A. In addition, the tip end portion of the side surface portion 202A of the reflective sheet 200A is processed into a zigzag shape.

If such processing is not performed on the side surface portion 202A, the upper surface of the tip portion of the side surface portion 202A is linear, and if there is a corner between the upper surface and the side surface, the reflection of light will be reduced with this corner as the boundary. The directions are quite different, and as a result, not much light reaches the corresponding position of the corner to create a linear shadow, which is therefore processed in order to avoid it.

Therefore, the shape of the tip portion of the side surface portion 202A is not limited to the zigzag shape, and may be, for example, a wavy shape, or may be a mixture of the zigzag shape and the wavy shape. In addition, what is necessary is just to process not the whole front-end|tip part of 202 A of side surfaces, but at least a part included.

Furthermore, the number and size of the teeth are not limited to the scheme shown in Figure 9. Extremely speaking, even if only one or two very large teeth are designed, there is a certain effect, or even in the side part The upper surface of the top end portion of 202A is provided with a circular arc, and no corner between the upper surface and the side surface is formed on the top end portion of the side portion 202A, which also has a certain effect.

In addition, the shape of the teeth is not limited to that shown in FIG. 9 . For example, although FIG. 9 shows that the tooth portion has a left-right symmetrical shape, one side of the tooth portion may have a relatively gentle inclination in the range of, for example, 30° to 60° relative to the bottom surface of the tooth portion, and the other side may be opposite to the bottom surface of the tooth portion. It is an inclined shape substantially perpendicular to the bottom surface, for example, 80° to 90°.

In addition, if an example is shown, it is sufficient that the bottom of the teeth is 2.0 mm to 4.0 mm, and the height of the teeth is about 1.0 mm to 2.0 mm. Even in the case of waves, it only needs to be set to the same shape and size. Therefore, it is only necessary to set the 1/2 cycle to about 2.0mm~4.0mm and the amplitude to 0.5mm~1.0mm.

In addition, although not necessarily limited thereto, as long as the height from the bottom surface of the reflective sheet 200A to the bottom of the tooth portion and the height from the bottom surface to the top of the tooth portion are set to be 50% to 50% of the height of the side surface portion 202A, respectively. 90%, 90%~100% is enough. Furthermore, what is necessary is just to set the width of the bottom part of a tooth part to 2.5% - 10% with respect to the width of 202 A of side surfaces.

In addition, although it is shown in FIG. 9(b) that the tooth group consisting of a plurality of teeth is in the form of a horizontal straight line connecting the tops, the connecting line connecting the tops of the tooth group is adjacent to the center in the horizontal direction. A linear or curved shape such as a mountain shape may be used. In this way, since the light tends to go toward the four corners of the diffuser plate 300 , there is an advantage that the difference between brightness and darkness of the diffuser plate 300 as a whole is reduced.

In addition, in the case of setting the connecting line connecting the tops of the tooth group in a straight line, as shown in FIG. About half of becomes the height of the other tooth portion.

In addition, in the case of making the connecting line connecting the tops of the tooth part groups into a curved shape, as an example, one method is to set it so that when the horizontal direction is represented by x and the vertical direction is represented by y, use y= About 0.2x2 to 0.4x2 represents a curved line from the end of the tooth group to the center of the tooth group. In addition, as such a mountain type, about the bottom of each tooth. The height can also be set to the above-mentioned dimensions.

The size of the reflective sheet 200A is slightly larger than that of the diffuser plate 300 so that the diffuser plate 300 is embedded therein. The inner faces are opposite. That is, the bottom surface and the side surfaces of the diffuser plate 300 are covered with the first reflection surface 201Aa and the second reflection surface 202Aa of the reflection sheet 200A, respectively.

Therefore, the light emitted from the bottom surface of the diffuser plate 300 is reflected to the upper surface side of the diffuser plate 300 by the first reflective surface 201Aa, and the light emitted from the side surface of the diffuser plate 300 is reflected from the side surface of the diffuser plate 300 by the second reflective surface 202Aa. It enters into the diffusion plate 300 again, and is finally reflected to the upper surface side of the diffusion plate 300 .

Fig. 10 is a photograph showing the luminance distribution of light emitted from the lighting unit according to the present embodiment. In addition, in FIG. 10 , in order to explain the effect of the reflective sheet 200A of this embodiment, in addition to the brightness distribution ( FIG. 10( b )) in the case of using the reflective sheet 200A of this embodiment, The luminance distribution of the first embodiment (that is, the case where the reflective sheet 200 is used) is also shown ( FIG. 10( a )).

The matrix of 3 rows and 3 columns in Fig. 10(a) and Fig. 10(b) refers to the lighting unit shown in Fig. 9(a) respectively, and indicates that only the LED element 110 of the lighting unit in the second row and the second column is turned on. state.

Comparing Fig. 10(a) and Fig. 10(b), it can be seen that according to the structure of this embodiment, the light emitted from the side surface of the diffuser plate 300 of the lighting unit in the second row and the second column is diffused from the second reflective surface 202Aa. The side surface of the plate 300 enters the diffusion plate 300 again, and is finally reflected toward the upper surface side of the diffusion plate 300 and emitted from the upper surface of the diffusion plate 300 , so that the light can be effectively used. Therefore, if local dimming is performed using the structure of this embodiment, it is possible to accurately control the amount of light in each dimming area.

(third embodiment)

FIG. 11 is a diagram illustrating a configuration of a lighting unit 10A included in a lighting device according to a third embodiment of the present invention. Fig. 11(a) is a plan view, Fig. 11(b) is a bottom view, and Fig. 11(c) is an exploded perspective view.

As shown in FIG. 11 , the lighting unit 10A of this embodiment includes: a square plate-shaped LED unit 100A; a reflective sheet 200B arranged on the upper surface of the LED unit 100A; and, for example, two reflective sheets arranged on the upper surface of the reflective sheet 200B. Diffuser plate 600 .

Furthermore, the lighting unit 10A of the present embodiment differs from the lighting unit 10 of the first embodiment in the following two points: For example, two (X-axis direction)×for example one (Y-axis direction) LED elements 110 are mounted on the substrate. 101A; and one pattern corresponding to each LED element 110 is formed on each diffusion plate 600 (that is, one dimming area).

In addition, it should be understood that the size of the diffuser plate 600 of the present embodiment is substantially the same as the size of the diffuser plate 300 of the first embodiment. That is, in the present embodiment, the four dimming regions DE1 , DE2 , DE3 , and DE4 in the first embodiment are replaced by one dimming region (that is, the diffuser plate 600 ).

For example, two through-holes 200Ba corresponding to positions of, for example, two LED elements 110 and two through-holes 200Bb through which, for example, two protrusions 602 of the diffusion plate 600 pass, are formed in the reflective sheet 200B.

In this embodiment, as in the first embodiment, the reflective sheet 200B is arranged between the diffuser plate 600 and the substrate 101A. Even if the light emitted from the LED element 110 does not enter the diffuser plate 600 but reflection, or incident to the diffuser plate 600 but still emitted from the bottom surface of the diffuser plate 600, it will be reflected again toward the bottom surface of the diffuser plate 600 by the reflective sheet 200B, and incident to the diffuser plate 600 again, so the light emitted from the LED element 110 is almost All light exits from the upper surface of the diffusion plate 600 .

Like the diffuser 300 of the first embodiment, the diffuser 600 is arranged in the form of covering the reflective sheet 200B on the optical path of the light emitted from the LED elements 110, so that the light emitted from each LED element 110 passes through the diffuser. 600 is an optical element made of square plate-shaped optical glass or resin (such as acrylic, Pc (polycarbonate), etc.) that diffuses around the Z-axis.

FIG. 12 is a diagram illustrating the structure of a diffuser plate 600 according to this embodiment. Fig. 12(a) is a top view, Fig. 12(b) is a right side view, and Fig. 12(c) is a bottom view. In addition, FIG. 13 is a cross-sectional view illustrating the structure of the diffuser plate 600 . Fig. 13(a) and Fig. 13(b) are A-A sectional view and B-B sectional view of Fig. 12(c), respectively.

As shown in FIGS. 12( b ) and 12 ( c ), on the bottom surface of each diffuser plate 600 , for example, four cylindrical protrusions 602 protruding toward the negative side of the Z-axis are formed. If the diffusion plate 600 is placed on the reflective On the sheet 200B, each protrusion 602 passes through the through hole 200Bb of the reflective sheet 200B and the through hole 120a of the reinforcing plate 120, and protrudes toward the bottom surface side of the substrate 101A. The diffuser plate 600 is fixed to the substrate 101A by heat welding or the like on the bottom surface side of the substrate 101A ( FIG. 11( c )).

As shown in FIG. 12( a ), FIG. 13( a ), and FIG. 13( b ), a concave conical surface 610 is formed on the upper surface of each diffusion plate 600 corresponding to the position of, for example, one LED element 110 . If the light emitted from the LED element 110 passes through the diffusion plate 600 and reaches the concave conical surface 610, a part of the light is emitted from the concave conical surface 610, and the other part of the light is diffused in the diffusion plate 600 around the Z axis through the concave conical surface 610. . Thus, the uniformity of the diffuser plate 600 can be achieved.

As shown in FIGS. 12( a ) and 13 ( a ), notches 650 are formed at the four corners of the upper surface of the diffuser plate 600 . By emitting light from the cutout portion 650 , the amount of light leaked from the side surface of the diffuser plate 600 is reduced, and the total amount of light emitted from the upper surface of the diffuser plate 600 is increased.

In addition, for example, four protruding portions 619 protruding upward gradually from the central portion toward the four corners are arranged and formed on the diagonal line of the upper surface of the diffuser plate 600 . As described above, when four dimming areas DE1, DE2, DE3, and DE4 are formed in the first embodiment, for example, the number of LED elements 110 is also four correspondingly. When one dimming area is formed, the number of LED elements 110 is also one, so the maximum light intensity is 1/4 compared with the case of FIG. 3 , and the light intensity is reduced.

Furthermore, since the decrease in the light intensity becomes conspicuous at the four corners of the diffuser plate 600 , by providing the protruding portion 619 in the present embodiment, the decrease in the light intensity at the four corners is suppressed. In addition, by subjecting the upper surface of the protruding portion 619 to corrugation processing (concave-convex processing) with a difference in unevenness of about several tens of μm, it is possible to further suppress a decrease in the amount of light.

In addition, on the upper surface of the diffusion plate 600 , for example, eight grooves 611 extending from the four corners along each side are formed. The groove portion 611 functions as a waveguide, and when the light from each LED element 110 reaches the groove portion 611, it passes through the wall surface of the groove portion 611 and is reflected.

Therefore, leakage of light from each diffuser plate 600 (that is, each dimming area) to an adjacent dimming area can be suppressed. Further, grooves 613 each extending toward the concave conical surface 610 are formed at both end portions in the X-axis direction of the central portion in the Y-axis direction of the diffuser plate 600 . Each groove portion 613 is composed of, for example, four groove portions 613a, 613b, 613c, and 613d functioning as waveguides. When the light from the LED element 110 reaches the groove portions 613a, 613b, 613c, and 613d, it passes through the respective walls and faces the diffusion plate. 600 reflectors in the direction of the upper surface.

The positions where the grooves 613a and the like are formed are not limited to those shown in FIG. In this case, the adjacent groove portion 611 becomes shorter.

Incidentally, the formation positions of the grooves 611, 613a, etc., and 615 will be described as follows. In short, this is also the same in the case of the diffuser plate 300: the grooves 611, 613a, etc., and 615 should be properly formed on the physical surface with good balance. It is sufficient to deviate from the LED element 110 above. In this way, even when either the diffuser plate 300 or the diffuser plate 600 is used, light can be uniformly emitted from the upper surface thereof.

In addition, the diffusion plate 600 (that is, each dimming area) can suppress the leakage of light to the adjacent dimming area, similarly to the diffusing plate 300 . In addition, for example, eight arcuate grooves 615 centered on the concave conical surface 610 are formed in the vicinity of, for example, the four protrusions 619 on the upper surface of the diffuser plate 600 . The groove portion 615 functions as a waveguide, and when the light from each LED element 110 reaches the groove portion 615 , it is reflected by the wall surface of the groove portion 615 toward the upper surface of the diffuser plate 600 and emitted from the upper surface of the diffuser plate 600 .

As shown in Fig. 12(c), Fig. 13(a), and Fig. 13(b), on the bottom surface of each diffusion plate 600, a concave conical surface 620 formed at a position corresponding to the concave conical surface 610, and a concave conical surface corresponding to the concave conical surface The faces 620 are connected and selectively formed with circular openings 621 .

In addition, the concave conical surface 620 serves as an incident surface on which light emitted from the LED element 110 enters, and functions as a kind of condensing lens. Therefore, generally, although the light emitted from each LED element 110 has a large angular component (that is, has a large diffusion angle), when it enters each concave conical surface 620 , the diffusion angle becomes narrow.

As shown in Figure 12(c), Figure 13(a), and Figure 13(b), on the bottom surface of each diffuser plate 600, a plurality of annular grooves 622 are formed in a concentric circle shape to surround the concave conical surface 620. . In addition, the depth of the groove portion 622 is as deep as the groove portion 622 formed at a position deviated from the concave conical surface 620 ( FIG. 4( a )). Wide light is reflected in the direction of the upper surface of the diffuser plate 600 by the wall surface of the groove portion 622 , and is emitted from the upper surface of the diffuser plate 600 .

In addition, stepped portions 625 and 640 are formed on the bottom surface of the diffuser plate 600 . The stepped portion 625 is formed at the four corners, and the stepped portion 640 is formed at a position corresponding to the groove portion 613 . The stepped portion 625 and the like are all thinner than the peripheral portion.

In addition, a plurality of arc-shaped grooves 626 are formed in the stepped portion 625, and a plurality of arc-shaped grooves 641 whose depth gradually becomes deeper toward the outside are formed in the stepped portion 640 (FIG. 13(a), FIG. 13(b) ).

In addition, as shown in FIG. 12( c ), a plurality of circular recesses 631 , 633 are formed along each side at the end of the bottom surface of the diffuser plate 600 . When the light from each LED element 110 reaches the recesses 631 , 633 , it passes through the wall surfaces of the recesses 631 , 633 and is reflected toward the upper surface of the diffuser plate 600 .

In this way, in the diffuser plate 600 of this embodiment, for example, one pattern corresponding to, for example, one LED element 110 (that is, one diffuser element) is imposed to form one dimming area. Then, the light from the LED elements 110 is reflected toward the upper surface of the diffuser plate 600 by the concave conical surface 610 and the groove portion 622 formed in the diffuser plate 600 , and then exits from the upper surface of the diffuser plate 600 .

(fourth embodiment)

FIG. 14 is a plan view showing a modified example of the diffuser plate 600 according to the third embodiment of the present invention. As shown in FIG. 14 , a diffusion plate 600A of this embodiment (this modified example) differs from the diffusion plate 600 of the third embodiment in that, for example, four protrusions 619 are not formed on the upper surface.

FIG. 15 is a graph showing the luminance distribution of the lighting unit using the diffuser plate 600 of the third embodiment and the luminance distribution of the lighting unit using the diffuser plate 600A of the fourth embodiment. The graph on the left side of FIG. 15 is A graph showing the luminance distribution in one diagonal direction (direction A in FIG. 15 ) of the diffuser plate 600 and the diffuser plate 600A. The graph on the right side of FIG. The graph of the brightness distribution in the direction B of FIG. 15 .

As shown in FIG. 15, if the diffusion plate 600 and the diffusion plate 600A are used, the light emitted from the LED element 110 is diffused in the diffusion plate 600 and the diffusion plate 600A, so that the amount of light at a position close to the LED element 110 is relatively reduced, and Since the amount of light at a position deviated from the LED element 110 is relatively increased, light is emitted from the diffuser plate 600 and the diffuser plate 600A as a whole, and uniformity can be improved.

In addition, comparing the luminance distribution of the diffuser plate 600 and the luminance distribution of the diffuser plate 600A, it can be seen that the luminance distribution of the diffuser plate 600 is about 100 cd/m2 higher than that of the diffuser plate 600A. It can be seen that this is due to the influence of, for example, four protrusions 619 formed on the upper surface of the diffuser plate 600, and the protrusions 619 effectively function to improve brightness.

(fifth embodiment)

FIG. 17 is a diagram illustrating a modified example of the adjustment sheets 400A to 400C according to the fifth embodiment of the present invention, and corresponds to FIG. 6 . Instead of the star-shaped polygonal shape, FIG. 17(a) shows: a first sheet 410A with rounded ends; a second sheet 420A with rounded ends; and a third sheet 430A with rounded ends.

Fig. 17(b) shows: instead of the front end portion of the first sheet 410A, the first sheet 410B includes two types of substantially circular members, large and small; includes cut members at the four corners and a member located at the four corners and the approximate middle of the four corners. a second sheet 420B of a small substantially circular member; and a third sheet 430B including a small substantially circular member instead of each front end portion of the third sheet 430A.

Fig. 17 (c) shows: the first thin sheet 410C that the first thin sheet 410 shown in Fig. 6 (b) and the first thin sheet 410B shown in Fig. 17 (b) are combined; A second sheet 420C having the same shape as the second sheet 420 shown; and a third sheet 430C having the same shape as the third sheet 430 shown in FIG. 6( b ).

Also in the case of the adjustment sheets 400A to 400C shown in FIG. 17 , similarly to the case of the adjustment sheet 400 shown in FIG. 6 , the effects described using FIG. 16 can be obtained. Therefore, in this specification, the shapes of the first sheets 410A to 410C, the second sheets 420A to 420C, and the third sheets 430A to 430C constituting the adjustment sheets 400A to 400C as shown in FIG. 17 are also included in the star-shaped polygonal shape. .

In addition, the lighting unit using the diffusion plate 600 and the like described above can be used not only in a liquid crystal display attached to a personal computer, but also in a television such as a so-called liquid crystal television. In addition, this lighting unit can also be used in a device that does not have a liquid crystal panel but has a diffusion cover, a translucent resin plate, or the like, such as a general lighting device or a signboard device.

In addition, it should be considered that each embodiment disclosed this time is an illustration in all respects, and should not restrict this invention. The scope of the present invention is not limited by the above description, but is intended to include all changes within the meaning and range equivalent to the scope of the description shown in the description.

300: Diffusion plate

310: concave conical surface

311: Groove

650: Incision

DE1, DE2, DE3, DE4: dimming area

Claims (6)

A light distribution adjustment mechanism, characterized in that the light distribution adjustment mechanism is arranged on the optical path of the light emitted from the light-emitting element, adjusts the light distribution of the light, and has a layered structure formed of a plurality of layers, so The plurality of layers is in the shape of a sheet, and the closer to the side of the light-emitting element, the larger the radius. By stacking in the direction of the optical axis with the optical axis of the light-emitting element as the center, the overlapping degrees of the plurality of layers are different, On the other hand, it is configured so that the transmittance becomes higher as it deviates from the optical axis of the light emitting element, and a plurality of openings are formed in any one of the plurality of layers. The light distribution adjustment mechanism according to claim 1, wherein the plurality of layered structures are formed by stacking a plurality of substantially circular sheet members or films having different radii around the optical axis of the light emitting element. The light distribution adjustment mechanism according to claim 1, wherein the layers constituting the plurality of layers are star-shaped and polygonal. A lighting unit comprising: a substrate; a light emitting element disposed on the substrate; a square plate-shaped light distribution control element for controlling light distribution of light emitted from the light emitting element; and the The light distribution adjustment mechanism as described in Claim 1 attached to the light distribution control element. A display with the light distribution adjustment mechanism described in claim 1. A TV set having the light distribution adjustment mechanism described in claim 1.

Images