TWI494525B - Flat lighting apparatus - Google Patents

Description

Flat light fixture

This invention relates to a planar light fixture, and more particularly to a planar light fixture that provides an asymmetrical light shape.

The planar light fixture structure of the edge-lit LED may include a light-emitting diode light source, a light guide plate, a reflection sheet, an optical film, a diffusion sheet, and a machine member. In general, for illumination purposes, conventional edge-lit LED planar luminaires typically design the illumination beam to be symmetrical in the direction of the φ of the polar coordinates (ie, circularly symmetric in the horizontal direction). The observer is at different angles of φ and the received light intensity is consistent. In addition, if the area illuminated by the illumination beam provided by the planar luminaire is approximately circular, when the object to be illuminated is a long and narrow object, for example, a long and narrow type of painting, in order to illuminate the entire picture, the planar luminaire must be made. The illuminated range is larger than the long side of the painting, so most of the light in the short side of the painting will be wasted, which will reduce the lighting efficiency of the flat luminaire.

A light source luminaire for an edge-lit LED is disclosed in U.S. Patent Nos. 7,431,489 and 7,542,635. The light source lamp comprises a light source of the light emitting diode, a reflective sheet, a light guide plate and a diffusion sheet, wherein the diffusion sheet is internally doped with an asymmetric and one-dimensional rod-shaped diffusion particle, and the substrate of the diffusion sheet and the diffusion particle The difference in refractive index to achieve the scattering effect, the light source luminaire can control the angular spread of light by asymmetrically diffusing particles.

The invention provides a flat luminaire which can provide an asymmetric illumination light shape through the use of a diffusion sheet.

Other objects and advantages of the present invention will become apparent from the technical features disclosed herein.

In order to achieve one or a part or all of the above or other purposes, an embodiment of the present invention provides a planar light fixture comprising a light guide plate, a diffusion sheet and a light source. The light guide plate has a light incident surface, a light emitting surface and a bottom surface, wherein the light emitting surface is opposite to the bottom surface, and the light incident surface is connected to the light surface and the bottom surface. The diffusion sheet is disposed on the light emitting surface of the light guide plate. The diffusion sheet includes a plurality of diffusion microstructures, and a surface of each of the diffusion microstructures has a curvature along a first axis that is different from a curvature along a second axis, wherein the curvatures are not zero and the first axis It is perpendicular to the second axis. The light source is disposed adjacent to the light incident surface of the light guide plate and is adapted to provide a light beam, and the light beam is adapted to enter the light guide plate through the light incident surface and exit the light exit surface of the light guide plate. After passing through the diffuser, the light beam exiting the light exiting surface has a different diffusion angle of the light beam in the first axial direction than the diffusion angle in the second axial direction.

In an embodiment of the invention, the diffusion sheet further comprises a substrate having a first surface and a second surface opposite to the first surface, the first surface surface of the light guide surface of the light guide plate and the diffusion microstructures are located On the second surface of the substrate.

In an embodiment of the invention, the diffusion microstructures are arranged in parallel along a first direction and parallel along a second direction, and the first axis is substantially parallel to the first direction, and the second axis and the second direction are Essentially parallel.

In one embodiment of the invention, each of the diffusion microstructures is on the first axis A first axial length in the upward direction is greater than a second axial length in the second axial direction.

In an embodiment of the invention, the ratio of the first axial length to the second axial length is substantially less than or equal to 10 and greater than one.

In one embodiment of the invention, the surface of each of the diffusing microstructures substantially comprises an elliptical surface or a parabolic surface.

In one embodiment of the invention, the diffusion microstructures are of the same material as the substrate.

In one embodiment of the invention, the diffusion microstructures and the substrate are of different materials.

In one embodiment of the invention, the diffusion microstructures are raised from the surface of the substrate to form a diffusion sheet, and the diffusion microstructures face away from the light exit surface of the light guide plate.

In one embodiment of the invention, the diffusion microstructures are recessed from the surface of the substrate to form a diffusion sheet, and the diffusion microstructures face away from the light exit surface of the light guide plate.

In an embodiment of the invention, the planar light fixture further includes a reflective sheet disposed on a bottom surface of the light guide plate.

In one embodiment of the present invention, the planar light fixture further includes an optical film set disposed on the light exit surface of the light guide plate, wherein the optical film set includes at least one of a silicon film and a light enhancement film. In an embodiment of the invention, the optical film set is located between the diffusion sheet and the light guide plate, or the diffusion sheet is located between the optical film set and the light guide plate.

In an embodiment of the invention, the light guide plate is a wedge-shaped light guide plate.

In an embodiment of the invention, the planar light fixture further comprises a back plate, The light board and the light source are disposed on the back board.

In an embodiment of the invention, the planar light fixture further includes a frame that connects the back plate and fixes the light guide plate, the light source and the diffusion sheet.

In an embodiment of the invention, the planar light fixture further comprises a reflective sheet disposed between the light guide plate and the back plate

Based on the above, the planar light fixture of the present invention adjusts the light shape of the light beam emitted from the light guide plate by using the diffusion sheet, so that the light shape of the illumination light beam provided by the planar light fixture can be an asymmetric light shape, for example, an elliptical light shape. . In other words, when the planar illuminator illuminates the narrow target, it can concentrate the light on the target, and can improve the brightness contrast of the illuminated target and the surrounding environment, thereby highlighting the target being illuminated. Furthermore, since the illumination shape of the planar luminaire can conform to the object of the narrow shape, the proportion of the partial beam irradiated on the non-target object can be reduced, thereby improving the illumination efficiency, thereby improving the utilization rate of the light source and reducing the cost and Reduce power consumption.

The above described features and advantages of the present invention will be more apparent from the following description.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments. The directional terms mentioned in the following embodiments, such as up, down, left, right, front or back, etc., are only directions referring to the additional drawings. Therefore, the directional terminology used is for the purpose of illustration and not limitation.

1A is a partial cross-sectional view of a planar light fixture according to an embodiment of the present invention, 1B is a top view of the diffuser used in the planar luminaire of FIG. 1A, and FIG. 2A and FIG. 2B are respectively schematic diagrams showing the beam travel of the beam through the diffusion microstructures passing through different axial directions. Referring to FIG. 1A and FIG. 1B , the planar light fixture 1000 of the present embodiment includes a light guide plate 1100 , a diffusion sheet 1200 and a light source 1300 . The light guide plate 1100 has a light incident surface 1120, a light emitting surface 1140 and a bottom surface 1160. The light emitting surface 1140 is opposite to the bottom surface 1160, and the light incident surface 1120 is connected to the light surface 1140 and the bottom surface 1160. In this embodiment, the light guide plate 1100 is exemplified by the flat light guide plate illustrated in FIG. 1A, but is not limited thereto, and the light guide plate 1100 may also adopt other possible light guide structures, which will be followed in subsequent paragraphs. An example is given.

In addition, the light source 1300 is disposed adjacent to the light incident surface 1120 of the light guide plate 1100 and is adapted to provide a light beam L1, and the light beam L1 is adapted to enter the light guide plate 1100 through the light incident surface 1120 and exit the light exit surface 1140 of the light guide plate 1100, as shown in the figure. 1A is drawn. In this embodiment, the light source 1300 may be a light-emitting diode light strip. In particular, the light source 1300 of the present embodiment may include a circuit board 1320 and at least one light emitting diode chip 1340. The light emitting diode chip 1340 is disposed on the circuit board 1320 and electrically connected to the circuit board 1320. In addition, the LED wafer 1340 can have a light emitting surface 1342, wherein the light emitting surface 1342 is adapted to provide a light beam L1, as shown in FIG. 1A.

Referring to FIG. 1A and FIG. 1B , the diffusion sheet 1200 is disposed on the light-emitting surface 1140 of the light guide plate 1100 , and the diffusion sheet 1200 includes a plurality of diffusion microstructures 1220 , wherein a surface S1 of each of the diffusion microstructures 1220 is along the edge The curvature in a first axial direction A1 is different from the curvature along a second axial direction A2, and the first axial direction A1 is perpendicular to the second axial direction A2. In this reality In the embodiment, the diffusion sheet 1200 further includes a substrate 1240 having a first surface 1242 and a second surface 1244 opposite to the first surface 1242, and the first surface 1242 is opposite to the light emitting surface 1140 of the light guide plate 1100. Therefore, the light beam L1 emerging from the light-emitting surface 1140 can be sequentially emitted through the first surface 1242 and the second surface 1244 to the diffusion sheet 1200 when being transmitted to the diffusion sheet 1200. 1A, FIG. 2A and FIG. 2B are examples in which the diffusion microstructures 1220 are disposed on the second surface 1244 of the substrate 1240, and the diffusion microstructures 1220 may be different materials from the substrate 1240, but are not limited thereto. The diffusion microstructure may also be formed by forming a diffusion sheet from the second surface of the substrate to form a diffusion sheet, that is, the diffusion microstructure may be the same material as the substrate, and this part will be exemplified in the following paragraphs. Description.

In this embodiment, the diffusion microstructures 1220 may be arranged in parallel along a first direction P1 and in parallel along a second direction P2, and the first axis A1 is substantially parallel to the first direction P1. The second axial direction A2 is substantially parallel to the second direction P2, as illustrated in FIG. 1B. Additionally, a first axial length 1222 of each of the diffusing microstructures 1220 in the first axial direction A1 is substantially greater than a second axial length 1224 in the second axial direction A2. Specifically, the "first axial length 1222" in this embodiment refers to the maximum length of each diffusion microstructure 1220 in the parallel first axial direction A1, and the "second axial length 1224" refers to The maximum length of each diffusion microstructure 1220 in the second axial direction A2. In this embodiment, the ratio of the first axial length 1222 to the second axial length 1224 may be substantially less than or equal to 10 and greater than 1, that is, when the ratio is equal to 1, and if the light beam L1 is in front of the light passing through the diffusion sheet 1200 In the case of a symmetrical light shape, the light shape of the light beam L1 after passing through the diffusion sheet 1200 is still a symmetrical light shape. For example, a circular light shape means that when the light beam L1 passes through the diffusion sheet 1200, the diffusion angles of the light beams in all directions will be the same. However, when the ratio is less than or equal to 10 and greater than 1, and if the light beam L1 is in a symmetrical light shape before passing through the diffusion sheet 1200, the light shape of the light beam L1 after passing through the diffusion sheet 1200 may be non- A symmetrical light shape, such as an elliptical light shape or other elongated light shape, meaning that when the light beam L1 passes through the diffusion sheet 1200, the diffusion angles of the light beams in different axial directions will be different, and the optical principle of this part will be Described in the subsequent paragraphs.

In the present embodiment, since the surface S1 of each of the diffusion microstructures 1220 disposed on the second surface 1244 of the substrate 1240 has a curvature along the first axis A1 that is different from the curvature along the second axis A2. The first axial direction A1 is perpendicular to the second axial direction A2. Therefore, after the light beam L1 emerging from the light exiting surface 1140 passes through the diffusion sheet 1200, the diffusion angle θ 1 of the light beam L1 in the first axial direction A1 is different from that in the first axial direction A1. The diffusion angle θ 2 on the two-axis A2 is as shown in FIG. 2A and FIG. 2B , wherein FIG. 2A is a schematic cross-sectional view of the light beam taken along the line AA′ of FIG. 1B through the diffusion sheet, and FIG. 2B is a schematic view. A cross-sectional view of the light beam taken along the line BB' of FIG. 1B through the diffusion sheet is shown, and the AA' line and the BB' line are parallel first and second axial directions, respectively.

Referring to FIG. 2A, when the light beam L1 emerging from the light-emitting surface 1140 passes through the surface S1 of the diffusion sheet 1200 along the first axial direction A1, the diffusion angle of the light beam L1 in the first axial direction A1 is θ1. The diffusion angle defined by the example is the angle θ 1 between the beam L1 and the normal vector N1 of the second surface 1244 when the beam L1 is emitted from the diffusion sheet 1200. Next, referring to FIG. 2B, when the light beam L1 emerging from the light-emitting surface 1140 passes through the surface S1 of the diffusion sheet 1200 along the second axial direction A2, since the surface S1 of each diffusion microstructure 1220 is along the first The curvature in the axial direction A1 is different from the curvature in the second axial direction A2, so the diffusion angle of the light beam L1 in the second axial direction A2 is θ 2 , wherein the angle of the surface of the different curvatures converges or diverges the light beam It will be different, so the diffusion angle θ 1 is not equal to the diffusion angle θ 2 . In other words, the light shape of the entire light beam L1 of the light beam L1 after passing through the diffusion sheet 1200 can assume an asymmetrical light shape. In the present embodiment, the diffusion angle θ 2 is similarly defined by the angle between the light beam L1 and the normal vector N1 of the second surface 1244 when exiting the diffusion sheet 1200, as shown in FIG. 2B.

In addition, FIG. 3A is a schematic view showing the illumination light shape formed when the planar light fixture of the embodiment does not use the diffusion sheet, and FIG. 3B shows that the planar light fixture of the embodiment is formed by using the diffusion sheet having a plurality of diffusion microstructures. Schematic diagram of the illumination pattern. Specifically, if the planar luminaire 1000 of the embodiment does not use the diffusion sheet 1200 described above, the illuminating light formed by the luminaire 1000 may be the circular light shape T1 illustrated in FIG. 3A, wherein the circular light shape The T1 can be achieved by cutting the light-emitting surface 1140 of the light guide plate 1100 into a circular shape or covering the light-shielding plate 1100 with a light-shielding plate having a circular opening. The planar luminaire 1000 of the present embodiment can adjust the shape of the light beam L1 after exiting the light guide plate 1100 by using the diffusion sheet 1200 described above, wherein the surface S1 of each diffusion microstructure 1220 is along the first axial direction A1. The curvature is different from the curvature along the second axis A2, so that after the light beam L1 passes through each of the diffusion microstructures 1220, the diffusion angle θ 1 of the light beam L1 in the first axial direction A1 is different from that in the second axial direction. The diffusion angle θ 2 on A2, that is, the circular light shape T1 of Fig. 3A provided by the planar luminaire can be adjusted to the elongated light shape T2 of Fig. 3B, which is, for example, elliptical. In this way, when the planar luminaire 1000 illuminates the object of the elongated shape, It is possible to concentrate the light on the target while reducing the proportion of the partial light beam on the non-target, thereby improving the illumination efficiency.

In this embodiment, since the planar light fixture 1000 is a flat light guide plate, in order to improve the efficiency of the light beam L1 emerging from the light exit surface 1140 of the light guide plate 1100, the planar light fixture 1000 may include a reflective sheet 1400, wherein the reflective sheet 1400 is disposed. The bottom surface 1160 of the light guide plate 1100. Generally, the bottom surface 1160 of the light guide plate 1100 may also be provided with a light scattering microstructure (not shown), wherein the light scattering microstructure is mainly used to make the partial light beam L1 enter the light guide plate 1100 at an incident angle smaller than the critical angle. The light-emitting surface 1140 can pass through the light-emitting surface 1140 of the light guide plate 1100 and exit the light guide plate 1100. In addition, the other partial light beam L1 is transmitted to the reflection sheet 1400 disposed on the bottom surface 1160 of the light guide plate 1100 via the scattering action of the light scattering microstructure. At this time, the reflection sheet 1400 is adapted to reflect the light beam L1, and the light beam L1 sequentially passes through the bottom surface 1160 and the light exit surface 1140 of the light guide plate 1100 to be emitted outside the light guide plate 1100.

In addition, in order to further control the light uniformity and brightness of the light beam L1 emitted from the light-emitting surface 1140 of the light guide plate 1100, the planar light fixture 1000 of the present embodiment adopts the optical film set 1500 disposed on the light-emitting surface 1140 of the light guide plate 1100. Achieved. In the present embodiment, the optical film set 1500 includes at least one of a gusset and a light-increasing sheet, and the optical film set 1500 of the present embodiment is located between the diffusion sheet 1200 and the light guide plate 1100, as shown in FIG. 1A. In addition, in other embodiments, the optical film included in the optical film set 1500 may also be other optical films having suitable microstructures.

In this embodiment, the planar light fixture 1000 can include a back panel 1600 and A frame 1700, wherein the light guide plate 1100 and the light source 1300 are disposed on the back plate 1600, and the frame 1700 is coupled to the back plate 1600 and fixes the light guide plate 1100, the diffusion sheet 1200, and the light source 1300, as shown in FIG. 1A. In addition, the planar luminaire 1000 can also include a reflective sheet 1800 disposed between the light guide plate 1100 and the back plate 1600 and covering a portion of the light guide plate 1100.

4A is a cross-sectional view showing another embodiment of the diffusion sheet taken along line AA' of FIG. 1B, and FIG. 4B is another embodiment of the diffusion sheet taken along line BB' of FIG. 1B. Schematic diagram of the shape. Referring to FIG. 1B , FIG. 4A and FIG. 4B , the planar luminaire 1000 may also be selected as the diffusion sheet 1200 ′ as illustrated in FIGS. 4A and 4B , wherein the diffusion microstructure 1220 ′ is the second from the substrate 1240 ′. The surface 1244 is recessed to form the diffusion sheet 1200' and is integrally formed. Specifically, the diffusion micro-pattern as shown in FIG. 4A and FIG. 4B can be formed on the second surface 1244 of the diffusion sheet 1200' by a suitable printing imprinting, compression molding process, or etching process. Structure 1220'. In the present embodiment, since the diffusion sheet 1200' is a concept similar to the diffusion sheet 1200 described above, the difference is that only the diffusion microstructure 1220' is recessed from the second surface 1244 of the substrate 1240' to form the diffusion sheet 1200. Therefore, the diffusion angle θ 1 of the light beam L1 in the first axial direction A1 is similarly different from the diffusion angle θ 2 in the second axial direction A2, that is, the light beam L1 after passing through the diffusion sheet 1200' The light shape of the overall light beam L1 similarly exhibits the illumination beam L1 of the aforementioned elongated light shape T2. Based on the above, the above-described flat lamp 1000 can have the above-described advantages similarly to the diffusion sheet 1200' of the present embodiment.

In addition, in order to enable the above-described planar light fixture 1000 to provide an elongated illumination light shape, the planar light fixture 1000 can use the aforementioned diffusion sheets 1200 and 1200'. In addition, the diffusion sheet 1200 ′′ as shown in FIG. 5A and FIG. 5B can also be used, wherein FIG. 5A is a cross-sectional view showing another embodiment of the diffusion sheet taken along line AA′ of FIG. 1B , and FIG. 5B is a schematic cross-sectional view showing another embodiment of the diffusion sheet taken along the line BB' of FIG. 1B. Specifically, in other words, the diffusion microstructure 1220" and the substrate 1240" may belong to the same material, and the specific The formation method can form a diffusion microstructure 1220 as shown in FIG. 5A and FIG. 5B on the second surface 1244 of the substrate 1240" through a suitable printing imprinting, compression molding process, or etching process. That is, the diffusion microstructure 1220 is a structure integrally formed from the second surface 1244 of the substrate 1240" to form the diffusion sheet 1200", as shown in FIGS. 5A and 5B.

Figure 6 is a partial cross-sectional view showing a planar light fixture according to another embodiment of the present invention. Referring to FIG. 1A and FIG. 6 simultaneously, the planar luminaire 2000 of the present embodiment adopts the concept similar to that mentioned by the planar luminaire 1000, except that the light guide plate 2100 adopts a wedge-shaped light guide plate as shown in FIG. 6 . In other words, the planar luminaire 2000 also has the advantages mentioned in the aforementioned planar luminaire 1000, and will not be described again here. It should be noted that the diffusion sheet 2200 used in the planar lamp 2000 may employ the aforementioned diffusion sheets 1200, 1200', 1200".

Figure 7 is a partial cross-sectional view showing a planar light fixture according to still another embodiment of the present invention. Referring to FIG. 1A and FIG. 7 simultaneously, the planar light fixture 3000 of the present embodiment adopts the concept similar to that mentioned by the planar light fixture 1000, except that the diffusion sheet 1200 is located between the optical film set 1500 and the light guide plate 1100. , as shown in Figure 7. Therefore, unlike the transmission path of the light beam L1 of the planar light fixture 1000, in the planar light fixture 3000, the light shape of the light beam L1 emerging from the light exit surface 1140 of the light guide plate 1100 first passes through the diffusion sheet 1200 and is diffused by the diffusion sheet 1200. The shape is shaped into a narrow shape and then transmitted to the optical film set 1500. In other words, the planar light fixture 3000 also has the advantages mentioned in the aforementioned planar light fixture 1000, and will not be described again here. It should be noted that the flat lamp 3000 may also use the aforementioned diffusion sheets 1200', 1200".

It should be noted that the surface S1 of each of the diffusion microstructures 1220, 1220', and 1220" may be an elliptical curved surface or a parabolic curved surface. The present embodiment has an elliptical curved surface as an implementation description, but is not limited thereto.

In summary, the planar luminaire of the present invention can adjust the shape of the light beam emerging from the light guide plate by using a diffusion sheet, wherein the curvature of the surface of each diffusion microstructure on the light guide plate along the first axial direction is Different from the curvature along the second axis, after the light beam passes through each diffusion microstructure, the diffusion angle of the beam in the first axial direction is different from the diffusion angle in the second axial direction, so the illumination light provided by the planar luminaire The shape can be adjusted to an asymmetrical light shape, for example: an ellipse. In other words, when the planar illuminator illuminates the narrow target, it can concentrate the light on the target, and can improve the brightness contrast of the illuminated target and the surrounding environment, thereby highlighting the target being illuminated. Furthermore, since the illumination shape of the planar luminaire can conform to the object of the narrow shape, the proportion of the partial beam irradiated on the non-target object can be reduced, thereby improving the illumination efficiency, thereby improving the utilization rate of the light source and reducing the cost and Reduce power consumption.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent. In addition, any embodiment or application of the present invention is not required to achieve all of the objects or advantages disclosed herein. Features. In addition, the abstract sections and headings are only used to assist in the search of patent documents and are not intended to limit the scope of the invention.

1000, 2000, 3000‧‧‧ flat lamps

1100, 2100‧‧‧ light guide

1120‧‧‧Into the glossy surface

1140‧‧‧Glossy

1160‧‧‧ bottom

1200, 1200', 1200", 2200‧‧‧ diffuser

1220, 1220', 1220" ‧‧‧ diffusion microstructure

1222‧‧‧First shaft length

1224‧‧‧Second axis length

1240, 1240', 1240" ‧ ‧ substrate

1242‧‧‧ first surface

1244‧‧‧ second surface

1300‧‧‧Light source

1320‧‧‧ boards

1340‧‧‧Light Emitter Wafer

1342‧‧‧Lighting surface

1400‧‧‧reflector

1500‧‧‧Optical diaphragm group

1600‧‧‧ Backplane

1700‧‧‧Frame

1800‧‧‧reflector

L1‧‧‧ Beam

S1‧‧‧ surface

A1‧‧‧first axial direction

A2‧‧‧second axial

P1‧‧‧ first direction

P2‧‧‧ second direction

N1‧‧‧ normal vector

T1‧‧‧round light shape

T2‧‧‧Slim long light shape

1A is a partial cross-sectional view of a planar light fixture in accordance with an embodiment of the present invention.

FIG. 1B is a top plan view of a diffusion sheet used in the planar lamp of FIG. 1A.

2A is a schematic cross-sectional view of the light beam taken along the line AA' of FIG. 1B through the diffusion sheet.

2B is a schematic cross-sectional view of the light beam taken along the line BB' of FIG. 1B through the diffusion sheet.

FIG. 3A is a schematic view showing the illumination light shape formed when the planar light fixture of the embodiment does not use a diffusion sheet.

FIG. 3B is a schematic view showing the illumination light shape formed by the diffuser having a plurality of diffusion microstructures in the planar lamp of the embodiment.

4A is a cross-sectional view showing an embodiment of another diffusion sheet taken along line AA' of FIG. 1B.

4B is a cross-sectional view showing an embodiment of another diffusion sheet taken along line BB' of FIG. 1B.

FIG. 5A is a cross-sectional view showing an embodiment of a further diffusion sheet taken along line AA' of FIG. 1B.

FIG. 5B is a cross-sectional view showing an embodiment of a further diffusion sheet taken along line BB' of FIG. 1B.

Figure 6 is a partial cross-sectional view showing a planar light fixture according to another embodiment of the present invention.

Figure 7 is a partial cross-sectional view showing a planar light fixture according to still another embodiment of the present invention.

1000‧‧‧ flat lamps

1100‧‧‧Light guide

1120‧‧‧Into the glossy surface

1140‧‧‧Glossy

1160‧‧‧ bottom

1200‧‧‧Diffuser

1220‧‧‧Diffusion microstructure

1240‧‧‧Substrate

1242‧‧‧ first surface

1244‧‧‧ second surface

1300‧‧‧Light source

1320‧‧‧ boards

1340‧‧‧Light Emitter Wafer

1342‧‧‧Lighting surface

1400‧‧‧reflector

1500‧‧‧Optical diaphragm group

1600‧‧‧ Backplane

1700‧‧‧Frame

1800‧‧‧reflector

L1‧‧‧ Beam

S1‧‧‧ surface

Claims (17)

A planar light fixture comprising: a light guide plate having a light incident surface, a light exit surface and a bottom surface, wherein the light exit surface is opposite to the bottom surface, and the light incident surface is connected to the light exit surface and the bottom surface; a diffusion sheet is disposed On the light-emitting surface of the light guide plate, the diffusion sheet includes a plurality of diffusion microstructures, and a surface of each of the diffusion microstructures has a curvature along a first axial direction different from a curvature along a second axial direction, wherein The light is not zero and the first axis is perpendicular to the second axis; and a light source is disposed beside the light incident surface of the light guide plate and adapted to provide a light beam, and the light beam is adapted to pass the light beam The light-incident surface enters the light guide plate and exits the light-emitting surface of the light guide plate, wherein the light-emitting surface of the light guide plate is circular to form a circular illumination light shape, and the light beam emitted from the light-emitting surface passes through the diffusion After the diffusion microstructures of the sheet, the diffusion microstructure of the diffusion sheet is emitted from the light exit surface by the diffusion angle of the light beam in the first axial direction being different from the diffusion angle in the second axial direction. The light shape of the beam is adjusted to be narrow Illumination light pattern. The flat luminaire of claim 1, wherein the diffuser further comprises a substrate having a first surface and a second surface opposite the first surface, the first surface facing the guide The light exiting surface of the light panel and the diffusion microstructures are on the second surface of the substrate. The planar luminaire of claim 1, wherein the diffusion microstructures are arranged in parallel along a first direction and are arranged in parallel along a second direction, and the first axial direction is substantially parallel to the first direction, The second axis is substantially parallel to the second direction. The planar luminaire of claim 1, wherein each of the diffusion microstructures has a first axial length in the first axial direction greater than a second axial length in the second axial direction. The planar luminaire of claim 4, wherein a ratio of the first axial length to the second axial length is substantially less than or equal to 10 and greater than one. The planar luminaire of claim 1, wherein the surface of each of the diffusion microstructures comprises substantially an elliptical surface or a parabolic surface. The flat luminaire of claim 2, wherein the diffusion microstructures are of the same material as the substrate. The flat luminaire of claim 2, wherein the diffusion microstructures and the substrate are of different materials. The planar luminaire of claim 1, wherein the diffusion microstructures are protruded from a surface of a substrate to form the diffusion sheet, and the diffusion microstructures face the illuminating surface away from the light guide plate. The planar luminaire of claim 1, wherein the diffusion microstructures are recessed from a surface of a substrate to form the diffusion sheet, and the diffusion microstructure faces the light exit surface away from the light guide plate. The flat luminaire of claim 1, further comprising a reflective sheet disposed on the bottom surface of the light guide plate. The flat luminaire of claim 1, further comprising an optical film set disposed on the light emitting surface of the light guide plate, wherein the optical film set comprises at least one of a cymbal and a brightness enhancement. The flat luminaire of claim 12, wherein the The optical film group is located between the diffusion sheet and the light guide plate, or the diffusion sheet is located between the optical film group and the light guide plate. The flat luminaire of claim 1, wherein the light guide plate is a wedge-shaped light guide plate. The flat luminaire of claim 1, further comprising a backplane, wherein the light guide and the light source are disposed on the backplane. The flat luminaire of claim 15, further comprising a frame connecting the back plate and fixing the light guide plate, the light source and the diffusion sheet. The flat luminaire of claim 15 further comprising a reflective sheet disposed between the light guide plate and the back plate.