CN114236902A

CN114236902A - Light distribution control element, light distribution adjustment mechanism, reflection member, reinforcing plate, illumination unit, display, and television

Info

Publication number: CN114236902A
Application number: CN202111329458.8A
Authority: CN
Inventors: 我妻透; 佐藤敦
Original assignee: Hu Su Ai Mei Jia Optical Technology Jiangsu Co ltd
Current assignee: Hu Su Ai Mei Jia Optical Technology Jiangsu Co ltd
Priority date: 2017-03-31
Filing date: 2018-03-29
Publication date: 2022-03-25
Also published as: TWI769733B; JP6786037B2; TWI782444B; CN110637238A; TW202131051A; CN114236901A; JP2019009105A; WO2018181701A1; JPWO2018181701A1; JP2019009107A; CN114236901B; JP2019009106A; TWI769235B; CN110637238B; TW201837531A; JP6818367B2; JP6818360B2; TW202125032A

Abstract

The present application provides a reflecting member, which is additionally disposed on a light distribution control element, the light distribution control element being a rectangular plate-shaped member having a groove portion formed therein and controlling the distribution of light emitted from a light emitting element, the reflecting member including: a 1 st reflecting surface and a 2 nd reflecting surface, the 1 st reflecting surface being in contact with an incident surface of the light distribution control element and reflecting light emitted from the incident surface side; the 2 nd reflecting surface faces several side surfaces of the light distribution control element, and reflects light emitted from the side surface side, and the light distribution control element includes: and a plurality of protrusions and a plurality of recesses formed at cross-sectional positions along a longitudinal direction of the light distribution control element passing through the protrusions, wherein through-holes are formed at positions corresponding to the protrusions on the 1 st reflecting surface, any one of tip portions of the 2 nd reflecting surface includes a zigzag or wavy shape, and a line connecting top portions of the tooth portion groups on the surface along the longitudinal direction on the 2 nd reflecting surface is formed in a mountain shape near a center in a horizontal direction.

Description

Light distribution control element, light distribution adjustment mechanism, reflection member, reinforcing plate, illumination unit, display, and television

The present application is filed as divisional application of application No. 201880023542.7, application No. 2018, 03, 29, and entitled "light distribution control element, light distribution adjusting mechanism, reflecting member, reinforcing plate, illumination unit, display, and television".

Background

The present invention relates to a light distribution control element, a light distribution adjustment mechanism, a reflection member, a reinforcing plate, an illumination unit, a display, and a television, and more particularly to a light distribution control element, a light distribution adjustment mechanism, a reflection member, a reinforcing plate, an illumination unit, a display, and a television, which are used in an illumination unit that irradiates light to a display panel from the rear surface side.

Conventionally, as a backlight of a transmission type 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.

In such a surface light source device, a thin device which uniformly irradiates a display region of a liquid crystal panel with uniform brightness has been demanded in the related art. In addition, in accordance with the demand for large-sized liquid crystal panels and high image quality, a technique of local dimming (dimming control for each region) is also put to practical use, in which the light quantity of LEDs is controlled one by one, thereby improving the contrast of different divided regions in the same screen or reducing power consumption. Such a surface light source device is disclosed in patent document 1, for example.

The surface light source device disclosed in patent document 2 includes an optical sheet module and a light source module having a plurality of LEDs as light sources. The optical sheet module includes a diffusion light guide plate or a diffusion plate, a reflection sheet, and the like, and repeatedly reflects light from the LED by the reflection sheet while diffusing the light by the diffusion light guide plate or the diffusion plate, thereby uniformly irradiating the liquid crystal display device with uniform brightness.

In such a surface light source device, in accordance with the demand for an increase in size and an increase in image quality of a liquid crystal panel, a local dimming (dimming control for each region) technique for increasing the contrast of different divided regions in the same screen or reducing power consumption by controlling the light amounts of LEDs one by one is also put to practical use. Such a surface light source device is disclosed in patent document 3, for example.

Documents of the prior art

Patent document 1: japanese patent application laid-open No. 2010-205698

Patent document 2: japanese patent laid-open publication No. 2005-352427

Patent document 3: japanese patent application laid-open No. 2010-205698

Disclosure of Invention

Technical problem to be solved by the invention

The surface light source device of patent document 1 reflects light from a light source by a concave mirror and irradiates the light toward a liquid crystal panel, and can form a beam shape into a substantially square shape similar to the shape of a divided region, and thus is most suitable for local dimming. However, in the configuration of patent document 1, it is assumed that the light source is disposed on the irradiation plane side with respect to the concave mirror, and the distance between the light source and the concave mirror needs to be increased, and therefore, it is difficult to make the apparatus itself thin.

As another problem, there is a problem that if the optical axis of each light source and the optical axis of each concave mirror do not match accurately, a desired light amount cannot be obtained in each divided region (that is, there is a difference in light amount dispersion). This problem also arises due to the deformation of the substrate on which the light source is mounted or the deformation of the concave mirror, and therefore suppression of these deformations is an extremely important problem. In order to suppress the deformation of the substrate or the deformation of the concave mirror, the substrate or the concave mirror may be thickened, but when such a method is adopted, the surface light source device itself becomes thicker or heavier.

Further, although the surface light source device of patent document 2 can uniformly irradiate the liquid crystal display device with uniform brightness, it is difficult to perform local dimming because the lights from the LEDs are diffused and mixed with each other by the diffusion plate and the reflection sheet.

On the other hand, in the surface light source device of patent document 2, the concave mirror reflects the light from the light source and irradiates the light toward the liquid crystal panel, and the shape of the light beam can be made substantially square similar to the shape of the divided regions, and therefore local dimming is most suitable, but since the configuration is such that only planar synthesis is performed on part of the illumination light emitted from the plurality of divided regions, the influence of the luminance distribution of the LED cannot be completely eliminated, and it is difficult to obtain substantially uniform illuminance distribution in the divided regions.

The invention provides a light distribution control element, a light distribution adjusting mechanism, a reflecting member, a reinforcing plate, an illumination 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 region.

Means for solving the problems

In order to achieve the above object, the present invention provides a light distribution control element in a square plate shape for controlling a light distribution of light emitted from a light emitting element, the light distribution control element including: a 1 st main surface opposed to the light emitting element; a 2 nd main surface which is a back surface with respect to the 1 st main surface; and a diffusing element that emits light from the light emitting element and enters the 1 st main surface after changing a traveling direction of the light emitted from the light emitting element to a direction substantially perpendicular to a light emitting surface of the light emitting element, and then emits the light from the 2 nd main surface.

With this configuration, since the traveling direction of light emitted from each light emitting element is diffused in a direction substantially perpendicular to the light emitting surface of the light emitting element by the diffusion element corresponding to each light emitting element, light beams having shapes similar to the shape of the divided region can be obtained while being thin.

Further, the 1 st main surface has: a circular concave incident surface formed at a position corresponding to the light emitting element; and a plurality of annular grooves formed concentrically so as to surround the incident surface, the 2 nd main surface including: and a 1 st emission surface formed by a conical concave surface formed at a position corresponding to the incident surface.

Preferably, notches are formed at four corners of the 2 principal surfaces. By emitting light from the cutout portion in this way, the amount of light leaking from the side surface of the light distribution control element is reduced, and the total amount of light emitted from the 2 nd main surface of the light distribution control element can be increased. Further, a plurality of waveguides may be formed at the edge portion of the 2 nd main surface, and reflection may be performed by wall surfaces of the waveguides. Here, the edge portion refers to an edge portion and/or a four-corner portion of the light distribution control element. In addition, the diffusion elements are preferably patterned in N square regions, respectively.

Preferably, the 2 nd main surface includes a protruding portion that gradually protrudes from a central portion toward four corner portions with respect to the 2 nd main surface.

Further, the present invention provides a light distribution adjusting mechanism which is arranged on an optical path of light emitted from the light emitting element to adjust a light distribution of the light and is attached to the light distribution control element, wherein the light distribution adjusting mechanism has a multi-layer structure, and may have a structure in which a transmittance decreases as the light emitting surface of the light emitting element is deviated.

According to the present invention, since the structure in which only the plane synthesis is performed on the partial illumination light emitted from the plurality of divided regions is not adopted, the influence of the luminance distribution of the LEDs can be eliminated, and a substantially uniform illuminance distribution can be obtained in the divided regions.

The multi-layer structure may be formed by stacking a plurality of substantially circular sheet members or films having different radii around the optical axis of the light-emitting element. Further, the plurality of layers constituting the multi-layer structure may have a star-shaped polygonal shape. Further, one or more openings may be formed in a part of the plurality of layer structures.

Further, the present invention provides a reflector attached to the light distribution control element, including: a 1 st reflecting surface which is in contact with an incident surface of the light distribution control element and reflects light emitted from the incident surface side; and a 2 nd reflecting surface which faces the plurality of side surfaces of the light distribution control element and reflects light emitted from the side surface side.

With this configuration, since the light emitted from the side surface of the light distribution control element is reflected by the 2 nd reflection surface and can be incident again from the side surface of the light distribution control element, the light leaking from the light distribution control element is reduced, and the light quantity of each light adjustment region can be accurately controlled.

Preferably, at least a part of the tip end portion of the side surface portion has a zigzag or wavy shape. Preferably, the reflecting member is formed of a thin plate of metal or resin having a thermal shrinkage rate of 0.5% or less. Further, the 1 st reflecting surface and the 2 nd reflecting surface preferably have a reflectance of 90% or more.

Further, the present invention provides a reinforcing plate for an illumination unit, the illumination unit including: a square plate-shaped substrate on the surface of which the light emitting element is mounted; and the light distribution control element disposed so as to face the light emitting element, wherein the reinforcing plate is made of a sheet metal having an L-shaped cross section and attached to reach a side surface from an upper surface of the substrate.

With this configuration, since the reinforcing plate can reliably suppress deformation of the substrate and the light distribution control element, displacement between the substrate and the light distribution control element does not occur.

In the case where the light distribution control element is provided in plurality, the reinforcing plate is preferably attached to a position at least over the adjacent light distribution control element. In addition, it is preferable that the illumination unit includes a reflecting member that is disposed between the substrate and the light distribution control element and reflects light from the light distribution control element, and the reinforcing plate is located between the reflecting member and the substrate.

From another aspect, an irradiation unit including any one of the light distribution control element, the light distribution adjustment mechanism, the reflection member, and the reinforcing plate according to the present invention includes: the light distribution control device includes a substrate, N light emitting elements arranged on the substrate, and the light distribution control element. The light distribution control element can be applied to a display or a television set attached to a personal computer or the like.

ADVANTAGEOUS EFFECTS OF INVENTION

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 flux similar to the shape of a divided region. Further, an illumination unit, a display, and a television provided with the light distribution control element can be realized.

Further, according to the present invention, it is possible to realize a light distribution adjusting mechanism for an illumination unit that is thin and can obtain a substantially uniform illuminance distribution in a divided region. Further, an illumination unit, a display, and a television provided with the light distribution adjustment mechanism can be realized.

Drawings

Fig. 1 is a perspective view showing a configuration of an illumination device according to embodiment 1 of the present invention.

Fig. 2 is an exploded perspective view illustrating a configuration of an illumination unit provided in the illumination device according to embodiment 1 of the present invention.

Fig. 3 is a diagram illustrating a structure of a diffusion plate of the lighting unit of fig. 2.

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

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

Fig. 6 is a diagram illustrating a structure of an adjustment sheet of the illumination unit of fig. 2.

Fig. 7 is a schematic diagram illustrating the operation and effects of the diffuser plate and the adjustment sheet of the illumination unit provided in the illumination device according to embodiment 1 of the present invention.

Fig. 8 is a photograph and a graph showing a luminance distribution of light emitted from the illumination unit included in the illumination device according to embodiment 1 of the present invention.

Fig. 9 is a diagram showing a configuration of an illumination unit provided in an illumination device according to embodiment 2 of the present invention.

Fig. 10 is a photograph showing a luminance distribution of light emitted from the illumination unit included in the illumination device according to embodiment 2 of the present invention.

Fig. 11 is a diagram showing a configuration of an illumination unit provided in an illumination device according to embodiment 3 of the present invention.

Fig. 12 is a diagram illustrating a structure of a diffusion plate of the illumination unit of fig. 11.

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

Fig. 14 is a diagram illustrating a configuration of a diffuser plate of an illumination unit included in the illumination device according to embodiment 4 of the present invention.

Fig. 15 is a diagram showing the luminance distribution of an illumination unit using the diffuser plate of embodiment 3 and the luminance distribution of an illumination unit using the diffuser plate of embodiment 4.

Fig. 16 is a diagram illustrating the operation and effect of the adjustment sheet 400 shown in fig. 6.

Fig. 17 is a diagram showing a modification of the adjustment sheet according to embodiment 5 of the present invention.

Fig. 18 is a modification of the diffuser plate 300 shown in fig. 3 and 4, and corresponds to fig. 3 (c).

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals, and description thereof will not be repeated.

(embodiment 1)

Fig. 1 is a perspective view showing a configuration of an illumination device 1 according to embodiment 1 of the present invention. The illumination device 1 is a surface light source device which is disposed on the back side of a liquid crystal panel, not shown, and irradiates the liquid crystal panel with light. As shown in fig. 1, the illumination device 1 is configured by arranging a plurality of illumination units 10 in a matrix according to the size of a liquid crystal panel.

Fig. 2 is an exploded perspective view illustrating a configuration of the illumination unit 10 that is a part of the illumination device 1 shown in fig. 1. As shown in fig. 2, the illumination unit 10 includes: the LED lighting device includes a rectangular plate-shaped LED unit 100, a reflective sheet 200 disposed on an upper surface of the LED unit 100, for example, 2 diffusion plates 300 disposed on an upper surface of the reflective sheet 200, and a regulation sheet 400 disposed on each diffusion plate 300, wherein, for example, four regulation sheets 400 are disposed for each diffusion plate 300.

Hereinafter, in the present specification, the longitudinal direction of the LED unit 100 is defined as the X-axis direction, the short-axis direction is defined as the Y-axis direction, and the direction orthogonal to the X-axis direction and the Y-axis direction (i.e., the emission direction of the LED element 110) is defined as the Z-axis direction. The positive direction side in the Z-axis direction may be referred to as "up" and the negative direction side as "bottom". Therefore, in the LED unit 100 of fig. 2, the surface facing the reflective sheet 200 is referred to as an upper surface, and the rear surface is referred to as a bottom surface.

The LED unit 100 of each lighting unit 10 includes: a substrate 101 in the shape of a square plate 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 reinforcing plates 120 mounted on the upper surface of the substrate 101. In addition, as another embodiment, an aluminum substrate, an FPC (Flexible printed circuits), or the like can be used for the substrate 101.

As shown in fig. 2, in the present embodiment, for example, 4 (X-axis direction) × 2 (Y-axis direction) LED elements 110 are mounted on the upper surface of the substrate 101 such that the direction of the optical axis coincides with the Z-axis direction, the pitch in the X-axis direction is 30mm, and the pitch in the Y-axis direction is 30mm, for example. On the substrate 101, an anode pattern (not shown) and a cathode pattern (not shown) for supplying power to each LED element 110 are formed, and each LED element 110 is electrically connected to the anode pattern and the cathode pattern, respectively.

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

In the present embodiment, the LED elements 110 are arranged in the respective divided regions for local dimming, and local dimming (i.e., dimming control for each divided region) can be performed by control of the drive circuit.

The reinforcing plate 120 is a thin plate-like metal (e.g., copper, iron, or aluminum) member for suppressing deformation of the substrate 101 and the diffusion plate 300. As shown in fig. 2, in the present embodiment, for example, 6 reinforcing plates 120 are surface-mounted by solder or the like (for example, conductive adhesive (silver paste), solder, soldering/welding, diffusion bonding, or the like) in an arrangement of 3 × 2 rows along each long side of the substrate 101.

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 and the side surface of the substrate 101. The cross section of each reinforcing plate 120 may be L-shaped, or may be コ -shaped and cover the bottom surface of the substrate 101. Further, for example, each reinforcing plate 120 may be provided with a V-shaped notch or a recess to improve the strength from the upper surface side toward the bottom surface side, for example, in the vicinity of the center portion of the outer surface at a position corresponding to the side surface of the substrate 101. Each reinforcing plate 120 is provided with, for example, two through holes 120a communicating with through holes (not shown) formed in the substrate 101. Each through hole 120a has a size through which the protrusion 302 (fig. 3b and 3 c) of the diffuser plate 300 can be inserted, and is disposed at a position corresponding to the protrusion 302 of each diffuser plate 300.

The protrusions 302 of the respective diffusion plates 300 are inserted into the through holes 120a and fixed by thermal fusion. In another embodiment, after applying an ultraviolet-curable adhesive or the like to each of the protrusions 302, ultraviolet rays may be further irradiated thereto to more firmly fix the substrate 101A to the protrusions.

The reinforcing plate 120 may be disposed along the long side of the substrate 101, and is not necessarily limited to a 3 × 2 row arrangement, but is preferably disposed so as to straddle at least 2 diffuser plates 300. With this configuration, since 2 diffusion 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 be suppressed.

The reflective sheet 200 is a member made of a square thin plate-like metal (e.g., aluminum) or resin (e.g., Polyethylene terephthalate) sandwiched between the diffuser plate 300 and the substrate 101. As shown in fig. 2, for example, 8 through holes 200a corresponding to the positions of, for example, 8 LED elements 110, and for example, 8 through holes 200b through which the protrusions 302 of the diffusion plate 300 pass are formed in the reflection sheet 200.

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

The diffusion plate 300 is an optical element made of optical glass or resin (e.g., acrylic, PC (polycarbonate), etc.) having a square plate shape, which is disposed on the optical path of the light emitted from the LED elements 110 so as to cover the reflection sheet 200, and diffuses the light emitted from each LED element 110 around the Z axis inside the diffusion plate 300.

Fig. 3 is a diagram illustrating a structure of a diffusion plate 300 according to the present embodiment. Fig. 3(a) is a plan view, fig. 3(b) is a left side view, and fig. 3(c) is a bottom view. Fig. 4 is a cross-sectional view illustrating the structure of the diffuser plate 300, and fig. 4(a) to 4(E) are a cross-sectional view a-a, a cross-sectional view B-B, a cross-sectional view C-C, a cross-sectional view D-D, and a cross-sectional view E-E, respectively, of fig. 3 (C).

As shown in fig. 3, for example, four dimming regions DE1, DE2, DE3, and DE4 for dimming by local dimming are formed in the diffusion plate 300 of the present embodiment by imposition of, for example, 4 patterns (i.e., 4 diffusion elements) corresponding to, for example, 4 LED elements 110.

In addition, as described above, in the present embodiment, since 8 LED elements 110 are arranged on the substrate 101, for example, 2 diffusion plates 300 are arranged in the X-axis direction as shown in fig. 2.

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

As shown in fig. 3(a) and 4(b), four concave conical surfaces 310 are formed on the upper surface of each diffuser plate 300, for example, so as to correspond to the positions of 4 LED elements 110, for example. When 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 is emitted from the concave conical surface 310, and the other part of the light is diffused in the diffusion plate 300 around the Z axis by the concave conical surface 310. Thereby, uniformity of the diffusion plate 300 is achieved.

As shown in fig. 3(a) and 3(b), notches 350 are formed at four corners of the upper surface of each diffusion plate 300. The cutout 350 reduces the amount of light leaking from the side surface of the diffuser 300 by emitting light in this manner, and increases the total amount of light emitted from the upper surface of the diffuser 300.

Further, for example, 2 grooves 311 extending in parallel, for example, are formed on the upper surface of each diffusion plate 300 inward from the substantially central portion of each side. The groove portions 311 function as waveguides, and when light emitted from the LED elements 110 reaches the groove portions 311, the light is reflected toward the upper surface of the diffusion plate 300 by the wall surfaces of the groove portions 311. Therefore, light leakage from each dimming range DE1, DE2, DE3, and DE4 to the adjacent dimming range can be suppressed. The groove 311 is not limited in shape, and may have a cross section in various shapes such as コ, U, and V shapes. Hereinafter, the same applies to other grooves (grooves 322a, etc.).

As shown in fig. 3(c), 4(b), and 4(d), the diffusion plates 300 each have, on the bottom surface thereof: for example, four concave conical surfaces 320 formed at positions corresponding to the four concave conical surfaces 310, and a circular opening 321 connected to each concave conical surface 320 and selectively formed. As will be described in detail later, in the present embodiment, each LED element 110 is housed in a space inside each circular opening 321 (a space including each concave conical surface 320 or each concave conical surface 320 when the LED element 110 has a certain height or when the circular opening 321 is not provided).

The concave conical surfaces 320 serve as incident surfaces on which light emitted from the LED elements 110 is incident, and function as a kind of condensing lens. Therefore, although the light emitted from each LED element 110 generally has a wide angular component (i.e., a large diffusion angle), the diffusion angle can be reduced by the light entering each concave conical surface 320.

As shown in fig. 3(c), 4(b), and 4(d), for example, 4

annular grooves

322a, 322b, 322c, and 322d are formed in this order on the bottom surface of each diffuser plate 300 so as to concentrically surround each concave conical surface 320. In the present embodiment, the

grooves

322c and 322d that are offset from the concave conical surface 320 are deeper than the

grooves

322a and 322b (fig. 4(b) and 4(d)), and light diffused by the concave conical surface 310 and light having a large diffusion angle emitted from the LED element 110 are reflected by the wall surfaces of the

grooves

322a, 322b, 322c, and 322d to the upper surface of the diffuser plate 300 and emitted from the upper surface of the diffuser plate 300.

As shown in fig. 4(b), a stepped groove 323 deeper than the groove 322c is formed in the center of the bottom surface of each diffusion plate 300, and the dimming regions DE1 and DE4 adjacent to each other in the Y-axis direction, or the dimming regions DE2 and DE3, respectively, are distinguished.

Similarly, as shown in fig. 4(d), a stepped groove 325 deeper than the

grooves

322c and 322d is formed in the substantially central portion of the bottom surface of each diffusion plate 300, thereby distinguishing the region DE1 and the dimming region DE2 adjacent to each other in the X-axis direction, or distinguishing the dimming region DE3 and the dimming region DE 4.

That is, in each dimming region, light diffused in the lateral direction (i.e., X-Y plane) is reflected toward the upper surface of the diffusion plate 300 by the wall surfaces of the

groove portions

323 and 325, and thus light leaking to the adjacent dimming region is reduced. Further, a plurality of steps 324 are formed to be thinner in a stepwise manner at both ends in the Y axis direction of the bottom surface of each diffusion plate 300 (fig. 4(b)), a plurality of steps 326 are formed to be thinner in a stepwise manner at both ends in the X axis direction (fig. 4(d)), and light diffused in the lateral direction of each dimming region (i.e., X-Y plane) is reflected in the upper surface direction of the diffusion plate 300 by the wall surfaces of the

steps

324, 326, whereby light leaking to the outside from both side surfaces in the Y axis direction and both side surfaces in the X axis direction is reduced.

As shown in fig. 3(c) and 4(a), for example, 3 groove portions 327 extending in parallel inward from the central portions of two opposite sides in the Y-axis direction are formed in the bottom surface of each diffusion plate 300. When the light emitted from each LED element 110 reaches the groove portion 327, the light is reflected toward the upper surface of the diffusion plate 300 by the wall surface of the groove portion 327, and therefore, the light leakage between the dimming range DE1 and the dimming range DE2, and between the dimming range DE3 and the dimming range DE4 adjacent to each other in the X-axis direction is reduced.

As shown in fig. 3(c) and 4(c), for example, 3 grooves 328 are formed in the bottom surface of each diffusion plate 300 so as to extend in parallel inward from substantially the center of two opposite sides in the X-axis direction. When the light emitted from each LED element 110 reaches the groove 328, the light is reflected toward the upper surface of the diffusion plate 300 by the wall surface of the groove 328, and therefore, the leakage light is reduced between the dimming range DE1 and the dimming range DE4 adjacent to each other in the Y-axis direction, and between the dimming range DE2 and the dimming range DE 3.

As shown in fig. 3(c) and 4(e), for example, 3 grooves 329 extending in the diagonal direction of the diffuser plate 300 are formed in the four corners of the bottom surface of each diffuser plate 300. When the light emitted from each LED element 110 reaches the groove 329, the light is reflected in the direction of the upper surface of the diffusion plate 300 by the wall surface of the groove 329. In addition, for example, 10 grooves 330 extending in the diagonal direction of the diffuser plate 300 are formed in the central portion of the bottom surface of each diffuser plate 300. When the light from each LED element 110 reaches the groove 330, the light is reflected toward the upper surface of the diffusion plate 300 by the wall surface of the groove 330.

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

In this way, in the diffusion plate 300 of the present embodiment, for example, 4 patterns (i.e., 4 diffusion elements) corresponding to, for example, 4 LED elements 110 are imposed, and the respective patterns are distinguished by the

grooves

323, 325, thereby forming, for example, 4 dimming regions DE1, DE2, DE3, and DE 4. The light from each LED element 110 is reflected in the upper surface direction of the diffusion plate 300 by the concave conical surface 310, the

grooves

322a, 322b, 322c, and 322d, and the like formed in each dimming region DE1, DE2, DE3, and DE4, and then emitted from the upper surface of the diffusion plate 300.

Fig. 18 is a modification of the diffuser plate 300 shown in fig. 3 and 4, and corresponds to fig. 3 (c). In fig. 18, slit regions 340A to 340D are shown in addition to the concave tapered surface 320, the groove 329, the recess 331, and the like described above.

The slit regions 340A are formed in the concave conical surfaces 320 of the diffuser plate 300 at 4 positions in total near the ends of the diffuser plate 300 in the short-side direction. The slit region 340A has a plurality of deep slits parallel to the longitudinal direction of the diffuser plate 300.

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

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

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

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

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

Here, as will be described later with reference to fig. 9, when the diffusion plate 300 is disposed in the reflective sheet 200 having the side surface portion 202A and the plurality of diffusion plates 300 are modularized to form the illumination unit 10 as shown in fig. 2, light is transmitted between the teeth of the side surface portion 202A, but in some cases, the diffusion plates 300 become dark.

In order to prevent this, the optical path may be changed in a direction perpendicular to the plane direction of the diffuser plate 300. In this case, it is effective to provide the

slit regions

340A, 340B.

In addition, only the slit region 340A may be provided, or only the slit region 340B may be provided. In this case, compared with the case where neither of the

slit regions

340A, 340B is provided, darkening between the diffusion plates 300 can be prevented.

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 diffusion plates 300 near the slit region 340B is easily formed to be larger than the gap between the diffusion plates 300 near the slit region 340A, and thus this is supplemented.

On the other hand, when the diffusion plate 300 becomes very large, since the pitch between the LED elements 110 becomes large, it is effective to provide the

slit regions

340C, 340D in order to emit light of uniform intensity.

In addition, only the slit region 340C may be provided, or only the slit region 340D may be provided. In this case, the intensity of light from the diffuser plate 300 can be improved as compared with the case where neither of the

slit regions

340C, 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, and the light intensity at the center between columns is lower than that at the center between rows, thereby complementing this.

Fig. 5 is an exploded perspective view illustrating the arrangement relationship between the diffuser plate 300 and the adjustment sheet 400 according to the present embodiment. Fig. 6 is a diagram illustrating the structure of the adjustment sheet 400, in which 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-like member, and is bonded to the concave conical surfaces 310 of the diffusion plate 300 so that the center thereof substantially coincides with the center of the light emitting surfaces of the LED elements 110, thereby adjusting the light distribution of the light emitted from the dimming regions DE1, DE2, DE3, and DE 4. However, the adjusting sheet 400 of the present embodiment is not necessarily bonded to the diffusion plate 300, and may be fixedly disposed on the optical path of the light emitted from the LED element 110 by some means.

As shown in fig. 6, the adjustment sheet 400 of the present embodiment is formed by sequentially laminating a 1 st sheet 410, a 2 nd sheet 420, and a 3 rd sheet 430 having different radii on a transparent film 405 by printing, vapor deposition, or the like in this order. The transparent film 405, the 1 st sheet 410, the 2 nd sheet 420, and the 3 rd sheet 430 according to this embodiment are each capable of transmitting a part of light from the LED element 110.

The transparent film 405 is made of, for example, PET having a thickness of 2.0 to 10 μm, and is obtained by punching (for example, Victoria punching) a urethane resin sheet having a thickness of 2.0 to 10 μm from the 1 st sheet 410, the 2 nd sheet 420, and the 3 rd sheet 430. In addition, sheet 1, sheet 2, and sheet 3 430 may be made of any other synthetic resin as long as the light distribution (i.e., transmittance) can be adjusted, such as nylon, and other embodiments may be used. The transparent film 405 may be provided with, for example, an adhesive layer on the diffuser plate 300 side as long as it can connect the diffusion plate 300 and the 1 st sheet 410 and the like. The 1 st sheet 410 and the like may be formed directly on the diffusion plate 300 by printing, vapor deposition, or the like, without providing the transparent film 405.

As shown in fig. 6(b), the 1 st sheet 410 is a sheet member having a 16-pointed star shape, for example. The 2 nd sheet 420 is a sheet member having a smaller radius than the 1 st sheet 410, for example, an 8-pointed star shape. The 3 rd sheet 430 is a sheet member having a smaller radius than the 2 nd sheet 420, for example, an 8-pointed star shape.

The transparent film 405, the 1 st sheet 410, the 2 nd sheet 420, and the 3 rd sheet 430 are coaxially arranged with their centers aligned, and the 2 nd sheet 420 is positioned on the 1 st sheet 410, and the 3 rd sheet 430 is positioned on the 2 nd sheet 420 and integrated (fig. 6 (a)). In addition, a circular opening 431 is formed in the center of the 3 rd sheet 430 of the present embodiment, and 8 circular openings 411, for example, arranged so as to surround the periphery of the 2 nd sheet 420 and 8 circular openings 412, for example, arranged outside the openings 411 are formed in the 1 st sheet 410.

Thus, in the adjustment sheet 400 of the present embodiment, the 2 nd sheet 420 and the 3 rd sheet 430 are overlapped with each other at the center portion (i.e., the portion where the opening 431 is formed), and the 1 st sheet 410, the 2 nd sheet 420, and the 3 rd sheet 430 are overlapped with each other at the outer side thereof. Further, the 2 nd sheet 420 and the 3 rd sheet 430 are overlapped on the outer side thereof, and a portion where the 1 st sheet 410 is present and a portion where the 1 st sheet 410 is not present (i.e., portions where the

openings

411, 412 are formed) are formed on the outer side of the 2 nd sheet 420.

Thus, if the overlapping degree of the 1 st sheet 410, the 2 nd sheet 420, and the 3 rd sheet 430 is different, the transmittance is different accordingly. In the present embodiment, the degree of overlapping of the 1 st, 2 nd, and 3

rd sheets

410, 420, and 430, and the size and position of the

openings

411 and 412 are adjusted according to the light distribution characteristics (i.e., luminance distribution) of the light from the LED element 110, and the transmittance is partially changed to adjust the luminance distribution to be substantially uniform as a whole.

Fig. 7 is a schematic diagram illustrating the effect of the diffusion plate 300 and the adjustment sheet 400 according to the present embodiment. Although fig. 7 schematically illustrates only the dimming range DE1 (i.e., only 1 diffusing element) for convenience of explanation, the same applies to the other dimming ranges DE2 to DE 4.

As shown in fig. 7, in the illumination unit 10 of the present embodiment, light (light rays) indicated by each arrow is emitted from the LED elements 110 arranged in the space inside the circular opening 321 of the diffusion plate 300.

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

When the light reaches the concave conical surface 310 in the front direction (upward direction in fig. 7), a part of the light is emitted from the concave conical surface 310 (arrow b), and the remaining light is reflected by the concave conical surface 310 and diffused in the diffuser plate 300 (arrows c and e). The light diffused in the diffuser plate 300 by the concave conical surface 310 enters the diffuser plate 300, is reflected in the upper surface direction of the diffuser plate 300 by the wall surfaces of the

grooves

322a, 322b, 322c, 322d, and the like, and is emitted from the upper surface of the diffuser plate 300 (arrow d).

Further, although a part of the light diffused by the concave conical surface 310 enters the inside of the diffuser plate 300 and is emitted from the side surface of the diffuser plate 300 (arrow e), when the diffuser plate 300 is used, most of the light from the LED element 110 can be finally emitted 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 illumination unit 10 of the present embodiment. Fig. 8 shows not only the luminance distribution in the case where the diffuser plate 300 and the adjustment sheet 400 are present (fig. 8 c), but also the luminance distribution in the case where the diffuser plate 300 and the adjustment sheet 400 are absent (i.e., the luminance distribution of light emitted from the LED elements 110) (fig. 8 a), and the luminance distribution in the case where the diffuser plate 300 is present but the adjustment sheet 400 is absent (i.e., the luminance distribution of light emitted from the diffuser plate 300) (fig. 8 b), in order to explain the effects of the diffuser plate 300 and the adjustment sheet 400 of the present embodiment.

In addition, the graphs of fig. 8(a) to 8(c) show the relative brightness of each photograph at each position in the axial direction and the Y-axis direction, respectively, corresponding to each photograph.

First, as can be seen by comparing fig. 8(a) and 8 (b): by using the diffusion plate 300, the amount of light is relatively decreased at a position close to the LED elements 110, and the amount of light is relatively increased at a position away from the LED elements 110, so that light is emitted from the diffusion plate 300 as a whole, and uniformity can be improved.

Further, as can be seen by comparing fig. 8(b) and 8 (c): in the present embodiment, since the adjustment sheet 400 is bonded to the concave conical surface 310 of the diffuser plate 300, the light (arrow b in fig. 7) emitted from the concave conical surface 310 is partially reflected by the adjustment sheet 400, and the reflected light is emitted from a position relatively deviated from the adjustment sheet 400. Therefore, hot spots (portions with high luminance) generated by the LED elements 110 can be suppressed, and light with a uniform light amount can be emitted from the entire diffusion plate 300.

Further, since the reflective sheet 200 (fig. 2 and 7) is disposed between the diffuser 300 and the substrate 101, the light emitted from the LED element 110 is reflected at the bottom surface of the diffuser 300, and is not directly incident on the diffuser 300, or is once incident on the diffuser 300, but is reflected by the concave conical surface 310 and then emitted from the bottom surface of the diffuser 300, and is reflected again by the reflective sheet 200 toward the diffuser 300 and is incident on the diffuser 300, and almost all the light emitted from the LED element 110 is emitted from the upper surface of the diffuser 300.

Fig. 16 is a diagram for explaining the operation and effect of the adjustment sheet 400 according to the present embodiment, and shows the luminance distribution of light emitted from the illumination unit 10 in the X-axis direction and the Y-axis direction. In fig. 16, "α" is a luminance distribution in the case where no adjustment sheet 400 is disposed, "β" is a luminance distribution in the case where only the 1 st sheet 410 is disposed, "γ" is a luminance distribution in the case where the 1 st sheet 410 and the 2 nd sheet 420 are disposed, and "δ" is a luminance distribution in the case where the 1 st sheet 410, the 2 nd sheet 420, and the 3 rd sheet 430 are disposed.

Table 1 shows the peak value of the luminance distribution (lower graph) in the X-axis direction in fig. 16 and the transmittance obtained from the peak value, and table 2 shows the peak value of the luminance distribution (right graph) in the Y-axis direction in fig. 16 and the transmittance obtained from the peak value.

[ TABLE 1 ]

	Peak value (cd/m)²)	Transmittance (%)
			α	3469.48	100
β	2579.12	74.3
			T-shirt	2381.45	68.6
δ	2343.00	67.5

[ TABLE 2 ]

	Peak value (cd/m)²)	Transmittance (%)
			α	3459.26	100
β	2584.78	74.7
			T-shirt	2330.79	67.4
δ	2294.17	66.3

As described above, the adjustment sheet 400 of the present embodiment is composed of the 1 st sheet 410, the 2 nd sheet 420, and the 3 rd sheet 430 formed on the transparent film 405. Therefore, the transmittance of the sheet 400 is adjusted to be low near the emission surface of the LED element 110 (i.e., "δ" in tables 1 and 2) and to be higher as the emission surface of the LED element 110 is deviated (i.e., "γ" and "β" in tables 1 and 2) toward the peripheral portion (see "δ" in tables 1 and 2).

Therefore, the luminance distribution of the light emitted from the diffusion plate 300 of the present embodiment has a peak on the emission surface of the LED element 110 as shown by "α" in fig. 16, but the luminance distribution of the light having passed through the adjustment sheet 400 is suppressed at the peak, and a substantially uniform luminance distribution can be obtained in each of the light adjustment regions DE1, DE2, DE3, and DE4 (see "δ" in fig. 16).

In the present embodiment, the 1 st sheet 410, the 2 nd sheet 420, and the 3 rd sheet 430 have a 3-layer structure, but the present invention is not limited to this structure, and for example, the thickness of each film may be changed, and the structure may be a 2-layer structure, or a structure having 4 or more layers. That is, the adjustment sheet 400 may have a multi-layer structure. This is the same as in embodiment 5 described later.

Although the present embodiment has been described above, the present invention is not limited to the above configuration, and various modifications may be made within the scope of the technical idea of the present invention.

For example, in the present embodiment, a case has been described in which 2 diffusion plates 300 are disposed on one substrate 101 on which 8 LED elements 110 are mounted, but the present invention is not limited to such a configuration, and for example, a plurality of substrates 101 corresponding to the size of the diffusion plates 300 may be employed.

In the diffuser plate 300 of the present embodiment, although the case where 4 patterns (i.e., 4 diffusing elements) are imposed in correspondence with 4 LED elements 110 has been described, the number of impositions is not limited to 4 as long as 1 diffusing element is arranged for each LED element 110. That is, for N (N is an integer of 1 or more) LED elements 110, N diffusing elements may be combined with the diffusion plate 300.

(embodiment 2)

Fig. 9 is a diagram showing a configuration of an illumination unit 10 according to embodiment 2 of the present invention. Fig. 9(a) is a view showing a state in which the diffuser plate 300 is attached to the reflective sheet 200A, and fig. 9(b) is a view showing a state in which the diffuser plate 300 and the reflective sheet 200A are disassembled.

The lighting unit of the present embodiment is different from that of embodiment 1 in that the reflective sheet 200A attached to the diffuser plate 300 is formed so as to surround the bottom surface and the side surfaces of the diffuser plate 300. In fig. 9, for convenience of explanation, only one diffuser plate 300 and one reflection sheet 200A are shown, and other structures are omitted, but the size of the reflection sheet 200A may be 2 times that of the diffuser plate 200A, for example, two diffuser plates 300 may be accommodated in one reflection sheet 200A.

As shown in fig. 9, the reflective sheet 200A (reflective member) of the present embodiment is formed of a metal thin plate (e.g., aluminum) or a resin (e.g., PET (Polyethylene terephthalate)), and has a reflectance of 90% or more and a heat shrinkage of 0.5% or less.

The reflective sheet 200A has a substantially square box shape with an open upper surface, and accommodates the diffusion plate 300 therein. The reflective sheet 200A includes: a bottom surface portion 201A formed to cover the bottom surface of the diffuser plate 300, and a side surface portion 202A formed to cover, for example, four side surfaces of the diffuser plate 300. In this case, the bottom surface portion 201A abuts against the bottom surface of the diffuser plate 300, which is the light incident surface. The side surface 202A faces the side surface of the diffuser plate 300.

A 1 st reflecting surface 201Aa is formed on the inner surface of the bottom surface portion 201A, and a 2 nd reflecting surface 202Aa is formed on the inner surface of the side surface portion 202A. Side surface portions 202A may or may not be connected to each other at short side portions. In the latter case, the reflection sheet 200A is not strictly box-shaped, but in this case, it can be said that it is box-shaped as a rough shape.

Further, 4 through holes 200Aa corresponding to the positions of the LED elements 110 and 4 through holes 200Ab through which the 4 protrusions 302 of the diffuser plate 300 pass are formed in the bottom surface portion 201A of the reflective sheet 200A, for example. The tip of the side surface 202A of the reflective sheet 200A is formed in a zigzag shape.

If the side surface portion 202A is not processed in this manner, the upper surface of the distal end portion of the side surface portion 202A is linear, and if there is a corner portion between the upper surface and the side surface, the reflection direction of light greatly differs at the corner portion as a boundary, and as a result, not much light reaches the corresponding position of the corner portion and a linear shadow is generated, and processing is performed to avoid this shadow.

Therefore, the shape of the tip of the side surface portion 202A is not limited to the zigzag shape, and may be, for example, a wave shape, or a shape in which zigzag and wave shapes are mixed. Further, the entire distal end portion of the side surface portion 202A may not be processed, but at least a part thereof may be processed.

Further, the number and size of the teeth are not limited to those shown in fig. 9, and in the extreme, even if only one or two or so large teeth are designed, there is a certain effect, or even if the arc is provided on the upper surface of the tip portion of the side surface portion 202A, there is a certain effect that the corner portion between the upper surface and the side surface is not formed on the tip portion of the side surface portion 202A.

The shape of the teeth is not limited to the shape shown in fig. 9. For example, although the tooth portions are shown in a bilaterally symmetrical shape in fig. 9, one side of the tooth portion may be inclined relatively gently in a range of, for example, 30 degrees to 60 degrees with respect to the bottom surface portion of the tooth portion, and the other side may be inclined substantially perpendicularly to the bottom surface portion, for example, in a range of 80 degrees to 90 degrees.

In addition, as an example, the bottom of the teeth may be set to 2.0mm to 4.0mm, and the height of the teeth may be set to about 1.0mm to 2.0 mm. Even in the case of the wavy shape, the same shape and size may be used, and therefore, the 1/2 period may be set to about 2.0mm to 4.0mm, and the amplitude may be set to 0.5mm to 1.0 mm.

Further, although not necessarily limited thereto, the height from the bottom surface of the reflection sheet 200A to the bottom of the tooth portion and the height from the bottom surface to the top of the tooth portion may be set to 50% to 90% and 90% to 100% respectively with respect to the height of the side surface portion 202A. Further, the width of the bottom of the tooth portion may be set to 2.5% to 10% with respect to the width of the side surface portion 202A.

Although fig. 9(b) shows that the tooth group including the plurality of teeth is a line connecting the respective tops and is a horizontal straight line, a connecting line connecting the respective tops of the tooth group may be a straight line or a curved line such as a mountain shape in the vicinity of the center in the horizontal direction. Thus, since light is easily directed to the four corners of the diffuser plate 300, there is an advantage that the difference in brightness of the diffuser plate 300 as a whole is small.

In addition, when the connecting line connecting the top portions of the tooth portion groups is provided linearly, as shown in fig. 9(c), one method is to make the height of one of the adjacent tooth portions to be about half the height of the other tooth portion.

In addition, when the connecting line connecting the top portions of the tooth portion groups is curved, as an example, there is a method of providing: in the case where the horizontal direction is represented by x and the vertical direction is represented by y, y is 0.2x²～0.4x²The left and right sides represent curved lines from the end portions of the tooth group to the center of the tooth group. As such a mountain shape, the bottom and height of each tooth portion can be set to the above-described dimensions.

The size of the reflective sheet 200A is slightly larger than the size of the diffuser plate 300 so that the diffuser plate 300 is fitted therein, and when the diffuser plate 300 is accommodated in the reflective sheet 200A, the bottom surface and the side surfaces of the diffuser plate 300 are arranged to face the inner surface of the reflective sheet 200A. That is, the bottom surface and the side surface of the diffuser plate 300 are covered with the 1 st reflecting surface 201Aa and the 2 nd reflecting surface 202Aa of the reflecting sheet 200A, respectively.

Therefore, the light emitted from the bottom surface of the diffuser 300 is reflected to the upper surface side of the diffuser 300 by the 1 st reflecting surface 201Aa, and the light emitted from the side surface of the diffuser 300 is again incident into the diffuser 300 from the side surface of the diffuser 300 by the 2 nd reflecting surface 202Aa, and is finally reflected to the upper surface side of the diffuser 300.

Fig. 10 is a photograph showing the luminance distribution of light emitted from the illumination unit of the present embodiment. In fig. 10, in order to explain the operation and effect of the reflective sheet 200A of the present embodiment, the luminance distribution (fig. 10(a)) of embodiment 1 (that is, the case of using the reflective sheet 200) is shown in addition to the luminance distribution (fig. 10(b)) of the reflective sheet 200A of the present embodiment.

The 3-row and 3-column matrix of fig. 10(a) and 10(b) is the lighting unit shown in fig. 9(a), and shows a state in which only the LED element 110 of the lighting unit in the 2 nd row and 2 nd column is on.

As can be seen by comparing fig. 10(a) and 10 (b): according to the configuration of the present embodiment, light emitted from the side surface of the diffusion plate 300 of the lighting unit in row 2 and column 2 is again incident into the diffusion plate 300 from the side surface of the diffusion plate 300 through the 2 nd reflection surface 202Aa, is finally reflected toward the upper surface side of the diffusion plate 300, and is emitted from the upper surface of the diffusion plate 300, so that light can be effectively utilized. Therefore, when local dimming is performed by the configuration of the present embodiment, the light amount of each dimming region can be accurately controlled.

(embodiment 3)

Fig. 11 is a diagram showing a configuration of an illumination unit 10A provided in the illumination device according to embodiment 3 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 illumination unit 10A of the present embodiment includes: a square plate-shaped LED unit 100A; a reflective sheet 200B disposed on the upper surface of the LED unit 100A; and, for example, 2 diffusion plates 600 disposed on the upper surface of the reflection sheet 200B.

The lighting unit 10A of the present embodiment is different from the lighting unit 10 of embodiment 1 in the following two points: for example, 2 (X-axis direction) × 1 (Y-axis direction) LED elements 110 are mounted on the upper surface of the substrate 101A; and 1 pattern (i.e., 1 dimming region) is formed on each diffusion plate 600 corresponding to each LED element 110.

It should be understood that the size of the diffusion plate 600 of the present embodiment is substantially the same as the diffusion plate 300 of embodiment 1. That is, in the present embodiment, the four dimming regions DE1, DE2, DE3, and DE4 of embodiment 1 are replaced by 1 dimming region (i.e., the diffusion plate 600).

In the reflective sheet 200B, for example, 2 through holes 200Ba corresponding to the positions of, for example, 2 LED elements 110, and for example, 2 through holes 200Bb through which, for example, 2 protrusions 602 of the diffuser 600 pass are formed.

In the present embodiment, as in embodiment 1, the reflective sheet 200B is disposed between the diffusion plate 600 and the substrate 101A, and even if the light emitted from the LED elements 110 is not incident on the diffusion plate 600 but is reflected on the bottom surface of the diffusion plate 600 or is once incident on the diffusion plate 600 but is emitted from the bottom surface of the diffusion plate 600, the light is reflected again toward the bottom surface of the diffusion plate 600 by the reflective sheet 200B and is incident on the diffusion plate 600 again, and therefore almost all the light emitted from the LED elements 110 is emitted from the upper surface of the diffusion plate 600.

The diffusion plate 600 is an optical element made of optical glass or resin (e.g., acrylic, Pc (polycarbonate)) having a square plate shape, which is disposed on the optical path of the light emitted from the LED elements 110 so as to cover the reflection sheet 200B and diffuses the light emitted from the LED elements 110 around the Z axis inside the diffusion plate 600, as in the diffusion plate 300 of embodiment 1.

Fig. 12 is a diagram illustrating a structure of a diffusion plate 600 according to the present embodiment. Fig. 12(a) is a plan view, fig. 12(b) is a right side view, and fig. 12(c) is a bottom view. Fig. 13 is a sectional view illustrating the structure of the diffuser plate 600. Fig. 13(a) and 13(B) are a sectional view a-a and a sectional view B-B of fig. 12(c), respectively.

As shown in fig. 12(b) and 12(c), for example, four columnar protrusions 602 protruding in the negative direction of the Z axis are formed on the bottom surface of each diffusion plate 600. When the diffuser plate 600 is placed on the reflective sheet 200B, the protrusions 602 protrude toward the bottom surface of the substrate 101A through the through-holes 200Bb of the reflective sheet 200B and the through-holes 120a of the reinforcing plate 120. The diffusion plate 600 is fixed to the substrate 101A by thermally welding or the like the protrusions 602 on the bottom surface side of the substrate 101A (fig. 11 c).

As shown in fig. 12(a), 13(a), and 13(b), one 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 inside of the diffusion plate 600 to reach the concave conical surface 610, a part of the light is emitted from the concave conical surface 610, and another part of the light is diffused in the diffusion plate 600 around the Z axis by the concave conical surface 610. Thus, uniformity of the diffusion plate 600 can be achieved.

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

Further, for example, four protruding portions 619 are formed on diagonal lines of the upper surface of the diffuser plate 600 so as to protrude upward gradually from the central portion toward the four corner portions. As described above, in the case where, for example, four light control regions DE1, DE2, DE3, and DE4 of embodiment 1 are formed, the number of LED elements 110 is 4 correspondingly, but in the case where 1 light control region is formed as in the present embodiment, the number of LED elements 110 is one, so that the maximum light amount is 1/4 and the light amount is reduced as compared with the case of fig. 3.

Since this reduction in light intensity is significant at the four corners of the diffuser plate 600, the projection 619 is provided in this embodiment, thereby suppressing the reduction in light intensity at the four corners. Further, by performing a corrugation process (uneven process) with an uneven difference of about several tens μm on the upper surface of the protruding portion 619, it is possible to further suppress a decrease in the light amount.

Further, for example, 8 groove portions 611 extending from four corners along each side are formed on the upper surface of the diffuser plate 600. The groove 611 functions as a waveguide, and when light from each LED element 110 reaches the groove 611, the light is reflected by the wall surface of the groove 611.

Therefore, light from each diffusion plate 600 (i.e., each dimming region) can be prevented from leaking into the adjacent dimming region. Grooves 613 extending toward the concave conical surface 610 are formed in both ends in the X-axis direction of the Y-axis direction center portion of the diffuser plate 600. Each groove 613 is formed by, for example, four

grooves

613a, 613b, 613c, and 613d functioning as waveguides, and when light from the LED element 110 reaches the

grooves

613a, 613b, 613c, and 613d, the light is reflected toward the upper surface of the diffusion plate 600 by the respective wall surfaces.

The positions where the grooves 613a and the like are formed are not limited to those shown in fig. 12(a), and may be formed at both ends in the Y-axis direction of the center in the X-axis direction of the diffusion plate 600. In this case, the groove 611 adjacent thereto becomes shorter.

The following description is given to the formation positions of the

grooves

611, 613a, etc. and 615, and in summary, the same applies to the diffuser plate 300: the

grooves

611, 613a, etc. and 615 may be appropriately formed at positions physically displaced from the LED element 110 with good balance. In this way, when either one of the diffusion plate 300 and the diffusion plate 600 is used, light can be uniformly emitted from the upper surface thereof.

Further, the diffusion plate 600 (i.e., each dimming region) can suppress leakage of light to the adjacent dimming region, as with the diffusion plate 300. Further, for example, 8 arc-shaped groove portions 615 centered on the concave conical surface 610 are formed in the vicinity of, for example, 4 protruding portions 619 on the upper surface of the diffuser plate 600. The groove portion 615 functions as a waveguide, and when light from each LED element 110 reaches the groove portion 615, the light is reflected in the direction of the upper surface of the diffusion plate 600 by the wall surface of the groove portion 615 and is emitted from the upper surface of the diffusion plate 600.

As shown in fig. 12(c), 13(a) and 13(b), a concave conical surface 620 formed at a position corresponding to the concave conical surface 610 and a circular opening 621 selectively formed in communication with the concave conical surface 620 are provided on the bottom surface of each diffuser plate 600.

The concave conical surface 620 serves as an incident surface on which light emitted from the LED element 110 is incident, and functions as a kind of condensing lens. Therefore, generally, although the light emitted from each LED element 110 has a large angular component (i.e., a large diffusion angle), the light enters each concave conical surface 620, thereby narrowing the diffusion angle.

As shown in fig. 12(c), 13(a), and 13(b), a plurality of annular grooves 622 are formed concentrically on the bottom surface of each diffuser plate 600 so as to surround the concave tapered surface 620. The depth of the groove 622 is as deep as the groove 622 formed at a position offset from the concave conical surface 620 (fig. 4 a), and light diffused by the concave conical surface 610 and light emitted from the LED element 110 with a wide diffusion angle are reflected in the upper surface direction of the diffusion plate 600 by the wall surface of the groove 622 and emitted from the upper surface of the diffusion plate 600.

Step portions

625 and 640 are formed on the bottom surface of the diffusion plate 600. The step portions 625 are formed at the four corners, and the step portions 640 are formed at positions corresponding to the grooves 613. The step portions 625 are thinner than the peripheral portions thereof.

Further, a plurality of arc-shaped grooves 626 are formed in the step portion 625, and a plurality of arc-shaped grooves 641 having a gradually increasing depth outward are formed in the step portion 640 (fig. 13(a) and 13 (b)).

As shown in fig. 12(c), a plurality of circular

concave portions

631 and 633 are formed along each side at the end of the bottom surface of the diffusion plate 600. When light from each LED element 110 reaches the

concave portions

631 and 633, the light is reflected toward the upper surface of the diffusion plate 600 by the wall surfaces of the

concave portions

631 and 633.

In this way, in the diffusion plate 600 of the present embodiment, for example, 1 pattern (i.e., 1 diffusion element) corresponding to, for example, 1 LED element 110 is imposed to form one dimming region. The light from the LED elements 110 is reflected toward the upper surface of the diffusion plate 600 by the concave conical surface 610, the groove 622, and the like formed in the diffusion plate 600, and then emitted from the upper surface of the diffusion plate 600.

(embodiment 4)

Fig. 14 is a plan view showing a modification of the diffuser plate 600 according to embodiment 3 of the present invention. As shown in fig. 14, a diffuser plate 600A according to the present embodiment (this modification) is different from the diffuser plate 600 according to embodiment 3 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 embodiment 3 and the luminance distribution of the lighting unit using the diffuser plate 600A of embodiment 4, the graph on the left side of fig. 15 is a graph showing the luminance distribution in one diagonal direction (direction a of fig. 15) of the diffuser plate 600 and the diffuser plate 600A, and the graph on the right side of fig. 15 is a graph showing the luminance distribution in the other diagonal direction (direction B of fig. 15) of the diffuser plate 600 and the diffuser plate 600A.

As shown in fig. 15, when the diffusion plate 600 and the diffusion plate 600A are used, the light emitted from the LED elements 110 is diffused in the diffusion plate 600 and the diffusion plate 600A, so that the amount of light at the positions close to the LED elements 110 is relatively reduced, and the amount of light at the positions away from the LED elements 110 is relatively increased, so that the light is emitted from the diffusion plate 600 and the diffusion plate 600A as a whole, and the uniformity can be improved.

Further, when the luminance distribution of the diffuser 600 and the luminance distribution of the diffuser 600A are compared, it is found that the luminance distribution of the diffuser 600 is higher than that of the diffuser 600A by substantially 100cd/m²Left and right. This is an effect of, for example, the four protrusions 619 formed on the upper surface of the diffusion plate 600, and the protrusions 619 effectively function to improve luminance.

(embodiment 5)

Fig. 17 is a diagram showing a modification of the adjustment sheets 400A to 400C according to embodiment 5 of the present invention, and corresponds to fig. 6. Instead of a star polygon shape, shown in fig. 17 (a): 1 st sheet 410A with rounded corners at each top end; a 2 nd sheet 420A having a part of its top end rounded; and a 3 rd sheet 430A each having a rounded top end.

Fig. 17(b) shows: a 1 st sheet 410B including two types of large and small substantially circular members instead of the front end portion of the 1 st sheet 410A; a 2 nd sheet 420B including a member having four corners cut and a small substantially circular member located substantially at the middle of the four corners; and a 3 rd sheet 430B including a small substantially circular member instead of the respective tip portions of the 3 rd sheet 430A.

Fig. 17(c) shows: a 1 st sheet 410C obtained by combining the 1 st sheet 410 shown in fig. 6(B) and the 1 st sheet 410B shown in fig. 17 (B); a 2 nd sheet 420C having the same shape as the 2 nd sheet 420 shown in fig. 6 (b); and a 3 rd sheet 430C having the same shape as the 3 rd sheet 430 shown in fig. 6 (b).

In the case of the adjustment sheets 400A to 400C shown in fig. 17, the same effects as described with reference to fig. 16 can be obtained as in the case of the adjustment sheet 400 shown in fig. 6. Therefore, in the present specification, the shapes of the 1 st, 2 nd, and 3 rd sheets 410A to 410C, 420A to 420C, and 430A to 430C constituting the adjustment sheets 400A to 400C shown in fig. 17 are also included in the star polygon shape.

The illumination unit using the diffusion plate 600 and the like described above can be used for a liquid crystal display attached to a personal computer, and can also be used for a television such as a so-called liquid crystal television. The illumination unit may be used for a device such as a general illumination device or a street signboard device which does not have a liquid crystal panel and has a diffusion cover, a light-transmitting resin plate, or the like.

It should be noted that the embodiments disclosed herein are illustrative in all respects and are not intended to limit the present invention. The scope of the present invention is not limited by the above description, but is intended to include all modifications within the meaning and scope equivalent to the scope of the claims as expressed in the claims.

Description of the reference numerals

1 Lighting device

10. 10A lighting unit

100. 100A LED unit

101. 101A substrate

110 LED element

120 reinforcing plate

120a through hole

200. 200A, 200B reflective sheet

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

201A bottom surface portion

201Aa 1 st reflecting surface

201Ab, 201Ac through-holes

202A side part

202Aa 2 nd reflecting surface

300. 600, 600A diffuser plate

302. 602 projection

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 step part

331. 631 and 633 concave parts

400 adjusting sheet

410 No. 1 sheet

411. 412 opening

420 nd sheet 2

430 rd sheet

431 opening

619A projection

Claims

1. A reflecting member, which is attached to a light distribution control element that controls the distribution of light emitted from a light emitting element and has a rectangular plate shape with a groove portion formed therein, is characterized in that,

the reflection member includes:

a 1 st reflecting surface which is in contact with an incident surface of the light distribution control element and reflects light emitted from the incident surface side; and

a 2 nd reflecting surface which faces the plurality of side surfaces of the light distribution control element and reflects light emitted from the side surface side,

the light distribution control element includes:

a protrusion; and

a plurality of concave portions formed at cross-sectional positions along a longitudinal direction of the light distribution control element passing through the protrusions,

a through hole is formed in the 1 st reflecting surface at a position corresponding to the projection,

the 2 nd reflecting surface has a tip portion having a sawtooth shape or a wavy shape, and a line connecting tip portions of the tooth group on the surface along the longitudinal direction on the 2 nd reflecting surface is formed in a mountain shape in the vicinity of a center in the horizontal direction.

2. The reflective member according to claim 1,

is formed of a metal or resin sheet having a heat shrinkage of 0.5% or less.

3. The reflective member according to claim 1,

the 1 st reflecting surface and the 2 nd reflecting surface have a reflectance of 90% or more.

4. An illumination unit, comprising:

a substrate;

a light-emitting element disposed on the substrate;

a rectangular plate-shaped light distribution control element for controlling the light distribution of the light emitted from the light emitting element and having a groove portion formed therein; and

the reflecting member according to claim 1 formed between the light distribution control element and the substrate,

the light distribution control element includes:

a protrusion; and a plurality of concave portions formed at cross-sectional positions along a longitudinal direction of the light distribution control element through the protrusions,