TWI420051B - Led surface illuminant device - Google Patents

Description

LED surface light source device

The present invention relates to a surface light source device, and more particularly to an LED surface light source device having a double prism sheet.

The LED is a point light source with a small illumination angle and strong directivity. In order to obtain a sufficiently large illumination area, the LED illumination device usually arranges a plurality of LEDs in an array. However, when a plurality of point light sources simultaneously illuminate an object, the illuminated object usually produces multiple shadows. In addition, the LED unit has a large luminous intensity, and forms a strong direct glare (bright spot) on the light-emitting surface of the LED lamp, and it is a point-like light source distributed from the outside. In order to avoid the generation of ghosting of the light source, a surface light source device with a good illumination function is obtained with the diffusion sheet, thereby obtaining uniform outgoing light. However, when light is transmitted through the diffusion sheet, part of the light is absorbed by the diffusion plate to cause partial light loss, thereby reducing the brightness of the emitted light.

In view of the above, it is necessary to provide an LED surface light source device which can improve the brightness and uniformity of emitted light and eliminate ghost images.

An LED surface light source device comprises a frame, a plurality of point light sources, a transparent first prism sheet and a transparent second prism sheet. The frame includes a bottom plate, and a plurality of point light sources are arranged on the bottom plate. The first prism sheet is disposed above the point source, and the second prism sheet is disposed at the first edge Above the lens, each has a light-incident surface and a light-emitting surface opposite to the light-incident surface, and a plurality of elongated arc-shaped protrusions are formed on the light-emitting surface of the first prism sheet, and the light-emitting surface of the second prism sheet is formed on the light-emitting surface of the second prism sheet The elongated V-shaped ridge structures extending in at least two different directions, the plurality of elongated V-shaped ridge structures extending in different directions are interdigitated. The first prism sheet is spaced apart from the point source by a first predetermined distance, and the second prism sheet is spaced apart from the first prism sheet by a second predetermined distance.

In the LED surface light source device of the present invention, after the light emitted by the point source passes through the first prism sheet and the second prism sheet, specific refraction, scattering, reflection, and diffraction are generated to achieve uniform emission in a specific viewing angle range. The generation of light source ghosting is avoided.

100‧‧‧LED surface light source device

10‧‧‧Frame

101‧‧‧floor

102‧‧‧ side wall

103‧‧‧ containment chamber

11‧‧‧ point light source

12‧‧‧First prism sheet

121, 131‧‧‧ into the glossy surface

122, 132‧‧‧ shine surface

123‧‧‧ bumps

13‧‧‧Second prism sheet

133, 1331, 1332, 1333, 1334‧‧‧ V-shaped ridge structure

134‧‧‧ Groove

135‧‧‧ four-pointed star

14‧‧‧protection board

1 is a schematic cross-sectional view showing an LED surface light source device of the present invention.

2 is a partial schematic view of the first prism sheet of FIG. 1.

3 is a perspective view of the second prism sheet of FIG. 1.

4 is a schematic view showing the light mixing of the first prism sheet to the point source in FIG.

Referring to FIG. 1 , the LED surface light source device 100 includes a frame 10 , a plurality of point light sources 11 , a first prism sheet 12 , a second prism sheet 13 , and a protective sheet 14 . The frame 10 includes a bottom plate 101 and a side wall 102 located around the bottom plate 101. The bottom plate 101 and the side wall 102 define a receiving cavity 103. The frame 10 may be made of metal or plastic having high reflectivity or made of metal or plastic coated with a high reflectivity coating. A plurality of point light sources 11 are arranged on the bottom plate 101. The first prism sheet 12 and the second prism sheet 13 have a size corresponding to the receiving cavity 103, and the first prism sheet 12 is located above the point light source 11, and the second prism The sheet 13 is located above the first prism sheet 12 and near the open end of the frame 10. The first prism sheet 12 and the second prism sheet 13 are both substantially parallel to the bottom plate 101. The first prism sheet 12 and the point light source 11 are spaced apart by a first predetermined distance. The second prism sheet 13 and the first prism sheet 12 are spaced apart by a second predetermined distance, which is not zero. The distance between the first prism sheet 12 and the point source 11 and the distance between the second prism sheet 13 and the first prism sheet 12 may be respectively set in advance according to actual needs, and the two distances may be equal or unequal. The protective plate 14 is made of one of transparent glass, frosted glass, transparent plastic plate and the like. The protective plate 14 is disposed above the second prism sheet 13 for protecting the surface of the microprism on the second prism sheet 13 from contamination or Scratch.

Referring to FIG. 2 , the first prism sheet 12 is made of a transparent plastic material, and has a light incident surface 121 and a light exit surface 122 opposite to the light incident surface 121 . The light incident surface 121 is planar and faces the point light source 11 . A plurality of elongated arcuate projections 123 are formed on the face 122. The cross section of the elongated arcuate projection 123 in a direction perpendicular to the longitudinal direction thereof may be one of a circular arc shape, an elliptical shape or a wave shape.

Referring to FIG. 3 , the second prism sheet 13 is made of a transparent plastic material, and has a light incident surface 131 and a light exit surface 132 opposite to the light incident surface 131 . The light incident surface 131 is planar and faces the first prism sheet 12 . The light-emitting surface 132 is formed with elongated V-shaped ridge structures 133 extending in at least two different directions, and the plurality of elongated V-shaped ridge structures 133 extending in different directions are interlaced with each other.

In this embodiment, the V-shaped ridge structure 133 extends in four different directions, and includes a plurality of elongated V-shaped ridge structures 1331 extending along the first direction X1, and a plurality of plurality of extending along the second direction X2. a long V-shaped ridge structure 1332, a plurality of elongated V-shaped ridge structures 1333 extending in the third direction X3, and a plurality of long lengths extending along the fourth direction X4 Strip V-shaped ridge structure 1334. Wherein, the plurality of elongated V-shaped ridge structures 1331 extending in the first direction X1 and the plurality of elongated V-shaped ridge structures 1333 extending in the third direction X3 are interlaced with each other, and a plurality of lengths extending in the second direction X2 A strip-shaped V-shaped ridge structure 1332 and a plurality of elongated V-shaped ridge structures 1334 extending in the fourth direction X4 pass through intersections of a plurality of elongated V-shaped ridge structures extending in the first direction X1 and the third direction X3 . In the four directions X1, X2, X3, and X4, angles θ1, θ2, θ3, and θ4 are formed between the adjacent two directions, and the included angles θ1, θ2, θ3, and θ4 are both 45 degrees. Moreover, the elongated V-shaped ridge structures 1331, 1332, 1333, and 1334 extending in four different directions are interlaced to form a plurality of closely-connected triangular pyramid grooves 134. Each of the four interconnected triangular pyramid grooves 134 having a common joint and their interconnected side walls form a quadrangular star 135, and the plurality of square stars 135 are arranged in an array.

Referring to FIG. 4, since a plurality of elongated arc-shaped protrusions 123 are formed on the light-emitting surface 122 of the first prism sheet 12, a specific refraction occurs when light emitted by the point source 11 passes through the light-emitting surface 122, thereby The light emitted from the point source 11 is diffused into a plurality of strip light sources 110. It can be understood that when the spacing between the respective point light sources 11 is sufficiently small, adjacent strip light sources overlap each other to cause light mixing. When the first prism sheet 12 is far away from the point light source 11, the longer the length of each strip light source 110 formed by the point source 11 on the light exit surface of the first prism sheet 12, a greater degree occurs between the strip light sources. Overlap, mixing more fully.

Then, the strip light source emitted from the first prism sheet 12 passes through the air layer and then enters the second prism sheet 13. Since the light exit surface of the second prism sheet 13 has a plurality of elongated V-shaped ridge structures 133, it can The light emitted from the second prism sheet 13 undergoes specific refraction, scattering, reflection, diffraction, and the like, thereby striping the strip light source from the first prism sheet 12. Further diffusing into a plurality of virtual light sources and collecting them in a specific viewing angle range, achieving an effect of uniform emission in a specific visual range, thereby avoiding generation of residual light source, and eliminating the need to provide a diffusion plate directly above the point light source 11.

It is to be understood by those skilled in the art that the above embodiments are only intended to illustrate the invention, and are not intended to limit the invention, as long as it is within the spirit of the invention Changes and modifications are intended to fall within the scope of the invention.

100‧‧‧LED surface light source device

10‧‧‧Frame

101‧‧‧floor

102‧‧‧ side wall

103‧‧‧ containment chamber

11‧‧‧ point light source

12‧‧‧First prism sheet

13‧‧‧Second prism sheet

14‧‧‧protection board

Claims (7)

An LED surface light source device comprises a frame, a plurality of point light sources, a transparent first prism sheet and a transparent second prism sheet, the frame comprises a bottom plate, a plurality of point light sources are arranged on the bottom plate, and the first prism sheet is arranged on the point light source The second prism sheet is disposed above the first prism sheet and has a light incident surface and a light exit surface opposite to the light incident surface, and the improvement is that the light incident surfaces of the first prism sheet and the second prism sheet are respectively a planar surface, a plurality of elongated arc-shaped protrusions are formed on the light-emitting surface of the first prism sheet, and an elongated V-shaped ridge structure extending in at least two different directions is formed on the light-emitting surface of the second prism sheet. The plurality of elongated V-shaped ridge structures extending in different directions are mutually staggered; the first prism sheet is spaced apart from the point source by a first predetermined distance, and the second prism sheet is spaced apart from the first prism sheet by a second predetermined distance. The LED surface light source device of claim 1, wherein the first prism sheet and the second prism sheet are respectively made of a transparent plastic material. The LED surface light source device according to claim 1, wherein the elongated protrusion formed on the light-emitting surface of the first prism sheet has a circular arc shape, an elliptical shape, and a wave section along a length perpendicular to the longitudinal direction thereof. One of the shapes. The LED surface light source device of claim 1, wherein the plurality of V-shaped ridge structures formed on the light-emitting surface of the second prism sheet extend in four different directions, and a plurality of lengths extending in the first direction The strip-shaped V-shaped ridge structure and the plurality of elongated V-shaped ridge structures extending in the third direction are interlaced with each other, and the plurality of elongated V-shaped ridge structures extending in the second direction and the plurality of lengths extending in the fourth direction The strip-shaped V-shaped ridge structure passes through intersections of a plurality of elongated V-shaped ridge structures extending in the first direction and the third direction. The LED surface light source device of claim 1, wherein the LED surface light source device further comprises a protection plate disposed above the second prism sheet, the protection plate is made of transparent glass, frosted glass, transparent plastic. Made of one of the board materials. The LED surface light source device of claim 1, wherein the frame is made of metal or plastic having high reflectivity. The LED surface light source device of claim 1, wherein the frame is made of metal or plastic coated with a high reflectivity coating.