TWM565324U - Direct-edge-lit thin planar light source device - Google Patents

Abstract

A planar light source device includes a substrate, a plurality of light emitting elements, and a light guide plate. The light emitting elements are disposed on the substrate. Each of the light-emitting elements has a light-emitting surface and a straight line perpendicular to the light-emitting surface and passing through the center of the light-emitting element. The light guide plate includes a first side surface adjacent to the substrate, a second side surface opposite to the first side surface, a plurality of first recesses formed on the first side surface and respectively received by the light emitting elements, and A plurality of recesses are formed on the second side and respectively correspond to the second grooves of the first grooves. Each of the first grooves is defined by a light entrance surface, and a light entrance surface extending from the periphery of the light entrance surface to the first side. Forming the first grooves by the first side of the light guide plate for the light-emitting elements, and the second side forms a structure design corresponding to the second grooves of the first grooves, To reduce the positive central brightness of each illuminating element, thereby making the viewing surface brightness more uniform.

Description

Thin planar light source device with light entering the lower side

The invention relates to a light source device, in particular to a thin planar light source device with light entering directly from the side.

In recent years, various light source devices have flourished. In the existing light source devices, a backlight module (BLM) is used as a bulk, and can be roughly classified into a direct type backlight module and a side light type backlight module. Group two.

Generally, the direct-lit backlight module can provide a higher brightness of the observation surface and a higher contrast ratio. However, due to factors such as the positional arrangement and the spacing of the light-emitting elements, the brightness of the overall light-emitting surface is further affected. Because the central brightness of the illuminating elements is relatively high, when arranged in an array form, the bright and dark areas are naturally distributed, and the brightness of the observation surface is uneven or the thickness of the module needs to be increased in exchange for uniformity, thereby causing the user to The shortcomings of poor visual experience. The edge-lit backlight module has the advantage of being thinner but limited by the limited position of the light source, so that high luminance cannot be achieved.

In addition, the existing backlight module requires an additional frame for the light-emitting components, which also causes an increase in volume, weight, and cost, and also limits the shape and appearance of the product.

Therefore, an object of the present invention is to provide a planar light source device which can improve the side-intensity light guiding and make the luminance limited and the thickness of the direct-type backlight cannot be thinned and the brightness of the observation surface is uneven.

Therefore, the novel planar light source device comprises a substrate, a plurality of light-emitting elements, and a light guide plate.

The substrate includes a first surface.

The light emitting elements are disposed on the first surface of the substrate. Each of the light-emitting elements has a light-emitting surface opposite to the first surface, and a line perpendicular to the light-emitting surface and passing through the center of the light-emitting element.

The light guide plate is disposed on the substrate, and includes a first side adjacent to the substrate, a second side opposite to the first side, and a plurality of recesses formed on the first side and respectively received by the light emitting elements The first groove, and the plurality of recesses are formed on the second side and respectively correspond to the second grooves of the first grooves. Each of the first grooves is defined by a light entrance surface, and a light entrance surface extending from the periphery of the light entrance surface to the first side.

Each of the light entrance masks has a first light incident surface and a second light incident surface. The first light incident surface surrounds the respective straight line, and the cross section has a first bus bar extending toward the second side and intersecting the straight line. The second light incident surface portion is located between the first light incident surface and the light incident surrounding surface and surrounds the respective straight lines, and has a cross section having a second bus bar extending toward the second side surface and intersecting the straight line. The angle formed by the intersection of the first busbar extensions is defined as Φ1, and the angle formed by the intersection of the second busbar extensions is defined as Φ2, and Φ1 is greater than Φ2.

The effect of the present invention is that the first grooves are formed by the first side of the light guide plate for the light-emitting elements, and the second side of the light guide plate is formed corresponding to the first grooves. The second grooves are structurally designed to reduce the brightness of the center of the light-emitting element and to increase the brightness between each of the two light-emitting elements, thereby obtaining a planar light source device having a more uniform viewing surface luminance.

Before the present invention is described in detail, it should be noted that in the following description, similar elements are denoted by the same reference numerals.

Referring to Figures 1, 2 and 3, a first embodiment of the planar light source device of the present invention comprises a substrate 1, a plurality of light-emitting elements 2, and a light guide plate 3.

The substrate 1 includes a first surface 11 and a second surface 12 opposite to the first surface 11.

The light emitting elements 2 are disposed on the first surface 11 of the substrate 1. Each of the light-emitting elements 2 has a light-emitting surface 21 opposite to the first surface 11, and a straight line L perpendicular to the light-emitting surface 21 and passing through the center of the light-emitting element 2. In this embodiment, each of the light-emitting elements 2 is a light-emitting diode (LED), and the main light-emitting intensity of each of the lateral light-emitting diodes is distributed with respect to the optical axis (optical axis). ) about ± (50 ° ~ 79 °), where the solid line in Figure 2 is the luminous intensity distribution of the lateral LED, the intensity of point A is the strongest, the dotted line is the distribution of the luminous intensity of the general LED, to O The intensity of the point is the strongest.

Referring to Figures 1, 3 and 4, the material of the light guide plate 3 is one of glass, polymethylmethacrylate (PMMA) and polycarbonate (PC). In the present embodiment, the material of the light guide plate 3 is exemplified by glass, but it is not particularly limited thereto. The light guide plate 3 is disposed corresponding to the substrate 1 and includes a first side surface 31 adjacent to the substrate 1 and a second side surface 32 opposite to the first side surface 31. The plurality of recesses are formed on the first side surface 31 and are respectively provided for The first recesses 33 of the light-emitting elements 2 and the plurality of recesses are formed on the second side surface 32 and correspond to the second recesses 34 of the first recesses 33, respectively.

Each of the first recesses 33 is defined by a light entrance surface 35 and a light entrance surface 36 extending from the periphery of the light entrance surface 35 to the first side surface 31. Each of the light entrance grooves 35 has a first light incident surface portion 351 surrounding the respective straight line L, and a first light incident surface portion 351 and the light incident surrounding surface 36 and surrounding the respective straight line L. The second light incident surface portion 352 and a third light incident surface portion 353 between the second light incident surface portion 352 and the light incident surrounding surface 36 and surrounding the respective straight line L.

The first light incident surface portion 351 has a cross section having a first bus bar M1 extending toward the second side surface 32 and intersecting the straight line L. The second light incident surface portion 352 has a cross section having a second bus bar M2 extending toward the second side surface 32 and intersecting the straight line L. The third light incident surface portion 353 has a cross section having a third bus bar M3 extending toward the second side surface 32 and intersecting the straight line L.

The angle formed by the intersection of the first bus bars M1 is defined as Φ1, the angle formed by the intersection of the second bus bars M2 is defined as Φ2, and the angle formed by the intersection of the third bus bars M3 is defined as Φ3, and Φ1 Greater than or equal to Φ2 is greater than or equal to Φ3. Preferably, in actual production, Φ1 is between 105 degrees and 160 degrees, Φ2 is between 80 degrees and 105 degrees, and Φ3 is between 30 degrees and 80 degrees.

The light guide plate 3 has the first recesses 33, and each of the first recesses 33 is substantially a plurality of light incident surface portions (ie, the first light incident surface portion 351, the second light incident surface portion 352, and the third light incident surface). The combination of the face 353) is designed to deflect the amount of light emitted directly above each of the light-emitting elements 2, thereby alleviating the problem of bright areas directly above each of the light-emitting elements 2. It is to be noted that the first bus bar M1 of the first light incident surface portion 351 may be a straight segment or an arc segment. Similarly, the second bus bar M2 may also be a straight segment or an arc segment. The third busbar M3 can also be a straight segment or an arc segment.

In addition, the number of the light-incident parts can be two or more, or two or more, or only the first light-injecting surface portion 351 and the second light-incident surface portion 352 are designed (and Φ1 is larger than Φ2). This also achieves the same effect and purpose of lowering the center luminance of the light-emitting element 2 and increasing the brightness between each two light-emitting elements 2.

Each of the second grooves 34 is defined by a light exit groove surface 37.

Each of the light exit groove surfaces 37 has a first total reflection surface portion 371 surrounding the respective straight line L, a second full portion between the first total reflection surface portion 371 and the second side surface 32 and surrounding the respective straight line L. a reflective surface portion 372, and a third total reflection surface portion 373 between the second total reflection surface portion 372 and the second side surface 32 and surrounding the respective straight line L. Referring to FIG. 5, the second side surface 32 may also form an inverted V-shaped, a positive V-shaped or an arc-shaped microstructure 40 in order to prevent adjacent light sources from interfering with each other.

Referring to FIGS. 1, 3 and 4, the first total reflection surface portion 371 has a cross section having a first sub-line S1 extending toward the first side surface 31 and intersecting the line L, the second total reflection surface portion 372 having a cross section having two a second sub-line S2 extending toward the first side surface 31 and intersecting the line L, the third total reflection surface portion 373 having a cross section having a second sub-line S3 extending toward the first side surface 31 and intersecting the line L . The angle formed by the intersection of the extensions of the first sub-lines S1 is defined as Θ1, and the angle formed by the intersection of the extensions of the second sub-lines S2 is defined as Θ2, and the angle formed by the intersection of the extensions of the third sub-lines S3 is defined as Θ3 And Θ1 is less than or equal to Θ2 is less than or equal to Θ3. Preferably, in actual production, Θ1 is between 20 degrees and 70 degrees, Θ2 is between 70 degrees and 135 degrees, and Θ3 is between 135 degrees and 180 degrees.

The light guide plate 3 has the second grooves 34, and each of the second grooves 34 is substantially a plurality of total reflection surfaces (ie, a first total reflection surface portion 371, a second total reflection surface portion 372, and a third total reflection portion). The design of the combination of the face 373) is also intended to deflect the amount of light emitted directly above each of the light-emitting elements 2, thereby alleviating the problem of bright areas directly above each of the light-emitting elements 2. It is to be noted that the first sub-reflections 371 may have a straight line segment or an arc segment. The second sub-line S2 may also be a straight segment or an arc segment. The third sub-line S3 may also be a straight line segment or an arc segment.

In addition, the number of total reflection surfaces described in the above paragraph can be more than two, and can be two or more; when two, only the first total reflection surface 371 and the second total reflection surface 372 are provided. The structural design (and Θ1 is less than Θ2), so that the same effect and purpose can be achieved.

In this embodiment, the first side surface 31 of the light guide plate 3 forms a plurality of microstructures 40. Preferably, the density of the microstructures 40 adjacent each of the light-emitting elements 2 is no greater than the density away from each of the light-emitting elements 2. It should be noted that the shape ratios of the microstructures 40 are merely schematic, and are drawn for enlargement for convenience of description, and the ratios thereof to other components are not actual ratios. Moreover, the microstructures 40 may be The actual optical requirements are designed to be V-shaped, dot-like, etc., and need not be specifically limited by the disclosure of the drawings.

A portion of the light path emitted by each of the light-emitting elements 2 of the novel planar light source device can be substantially as indicated by the dashed arrow in FIG.

Through the above description, the advantages of this embodiment can be summarized as follows:

The first recesses 33 are formed by the first side surface 31 of the light guide plate 3 for the light-emitting elements 2, and the second side surface 32 of the light guide plate 3 is formed to correspond to the first recesses. The second grooves 34 of the groove 33 are designed to reduce the brightness of the center of the light-emitting element 2, and the light rays of the light-emitting elements 2 are uniformly reflected and evenly distributed between each of the two light-emitting elements 2, thereby Obtain a more uniform effect on the brightness of the observed surface.

In addition, the present invention is used in combination with the side-emitting light-emitting element 2, and since the light-emitting elements 2 that are laterally emitted are light intensity that is directly above the lighter side, the present invention contributes to the overall light intensity. The light emitted by the light guide plate 3 on the second side surface 32 is evenly soft, so that the problem that the light-emitting element 2 that emits light in the forward direction will directly emit light from the second side surface 32 and cause uneven brightness and overall brightness will be avoided.

The plurality of microstructures 40 are formed by the first side surface 31 of the light guide plate 3, and the density of the microstructures 40 adjacent to each of the light-emitting elements 2 is not greater than the micro-locations away from each of the light-emitting elements 2. The density of the structure 40 allows the light to be more evenly distributed after diffusion through the microstructures 40.

3. The first recesses 33 are disposed on the light guide plate 3 for the light-emitting elements 2 to be disposed, and the light-emitting elements 2 can be directly disposed on the substrate 1 substantially parallel to the light guide plate 3, and There is no need to add a frame for the light-emitting elements 2 as in the prior art. Therefore, compared with the conventional backlight module, the present invention not only has the characteristics of light and thin, but also can achieve the effect of thin and no border at the same time. In the case of the existing backlight module, the case can maintain a lower cost under the effect of having no border, and thus has better market sales potential.

Referring to FIG. 6, a second embodiment of the planar light source device of the present invention is similar to the first embodiment. The difference between the second embodiment and the first embodiment is as follows:

The planar light source device does not need to include the microstructures formed on the first side surface 31 of the light guide plate 3, but instead is replaced by a diffuse reflection layer 41 located on the first side surface 31 of the light guide plate 3.

In addition, the planar light source device further includes a reflective sheet 42 disposed on the second surface 12 of the substrate 1 and an optical film 43 disposed on the second side surface 32 of the light guide plate 3.

Specifically, the optical film 43 can be a diffusion sheet or a brightness enhancement sheet or other optical film. The second embodiment can provide light by diffusing the light through the diffusion sheet. A more uniform distribution; or by setting the brightness enhancement to increase the overall brightness of the viewing surface.

Thus, the second embodiment can achieve the same purpose and effect as the first embodiment described above.

In summary, the novel planar light source device can achieve the purpose of the present invention.

However, the above is only the embodiment of the present invention, and when it is not possible to limit the scope of the present invention, all the simple equivalent changes and modifications according to the scope of the patent application and the contents of the patent specification are still This new patent covers the scope.

1‧‧‧Substrate
11‧‧‧ first surface
12‧‧‧ second surface
2‧‧‧Lighting elements
21‧‧‧Glossy
3‧‧‧Light guide plate
31‧‧‧ first side
32‧‧‧ second side
33‧‧‧First groove
34‧‧‧second groove
35‧‧‧Into the light trough surface
351‧‧‧First light-emitting face
352‧‧‧Second light-emitting face
353‧‧‧ Third light face
36‧‧‧Into the light
37‧‧‧Lighting groove surface
371‧‧‧First Total Reflection Face
372‧‧‧Second total reflection face
373‧‧‧The third total reflection face
40‧‧‧Microstructure
41‧‧‧Diffuse reflective layer
42‧‧‧reflector
43‧‧‧Optical diaphragm
L‧‧‧ Straight line
M1‧‧‧ first bus
M2‧‧‧Second bus
M3‧‧‧ third busbar
S1‧‧‧ first strand
S2‧‧‧ second strand
S3‧‧‧ third sub-line Φ1‧‧‧ angle Φ2‧‧‧ angle Φ3‧‧‧ angle Θ1‧‧‧ angle Θ 2‧‧‧ angle Θ3‧‧‧ angle

Other features and effects of the present invention will be apparent from the following description of the drawings, wherein: FIG. 1 is a schematic diagram showing a first embodiment of a planar light source device of the present invention; FIG. The luminous intensity distribution map illustrates the difference between the general LED and the lateral LED luminous intensity distribution; FIG. 3 is a partially enlarged schematic view of the first embodiment, illustrating that Φ1 is greater than Φ2 and greater than Φ3; FIG. 4 is a partial portion of the first embodiment. FIG. 5 is a schematic view similar to FIG. 1 , the main difference being that the second side of the first embodiment forms a plurality of microstructures; and FIG. 6 is a first embodiment of the novel planar light source device. A schematic cross-sectional view of a second embodiment.

Claims (13)

A planar light source device comprising: a substrate comprising a first surface; a plurality of light emitting elements disposed on the first surface of the substrate, each of the light emitting elements having a light emitting surface opposite to the first surface, and a vertical a light-emitting surface and a line passing through the center of the light-emitting element; and a light guide plate disposed corresponding to the substrate, and including a first side adjacent to the substrate, a second side opposite to the first side, and a plurality of recesses formed on the substrate a first groove for receiving the light-emitting elements, and a plurality of recesses formed on the second side and respectively corresponding to the second grooves of the first grooves, each of the first recesses The groove is defined by a light entrance groove surface, and a light entrance surface extending from the periphery of the light entrance groove surface to the first side surface, each of the light entrance groove masks has a first light incident surface, and surrounds the respective a straight line having a cross section having a first bus bar extending toward the second side surface and intersecting the straight line, and a second light incident surface between the first light incident surface and the light incident surrounding surface and surrounding each other The straight line and its profile And a second busbar extending toward the second side and intersecting the straight line defines an angle formed by the intersection of the first busbars as Φ1, and an angle formed by the intersection of the second busbars is defined as Φ2, and Φ1 is greater than Φ2. The planar light source device of claim 1, wherein each of the light entrance groove surfaces further has a third light incident surface between the second light incident surface and the light incident surface and surrounding the respective straight line. The third light incident surface has a cross section having a third bus bar extending toward the second side surface and intersecting the straight line, and defining an intersection angle formed by the intersection of the third bus bars is Φ3, and Φ2 is greater than Φ3. The planar light source device of claim 1, wherein each of the second grooves is defined by a light exit groove surface, each light exit mask has a first total reflection surface surrounding the respective straight line, and one is located a second total reflection surface between the first total reflection surface and the second side and surrounding the respective straight line, the first total reflection surface having a cross section having a second surface extending toward the first side and intersecting the line a sub-line having a second total reflection surface having a second sub-line extending toward the first side and intersecting the line, defining an angle formed by the intersection of the first sub-line extensions as Θ1, defining the first The angle formed by the intersection of the two sub-lines is Θ2, and Θ1 is smaller than Θ2. The planar light source device of claim 3, wherein each of the light exiting grooves has a third total reflection surface between the second total reflection surface and the second side and surrounding the respective straight line, the first The three total reflection surface has a cross section having a third sub-line extending toward the first side and intersecting the line, defining an angle formed by the intersection of the third sub-lines extending to be Θ3, and Θ2 is smaller than Θ3. The planar light source device of claim 1, wherein each of the light emitting elements is a lateral light emitting diode. The planar light source device of claim 1, wherein the first side of the light guide plate forms a plurality of microstructures. The planar light source device of claim 6, wherein the microstructures have a density at a location adjacent each of the light-emitting elements that is no greater than a density away from each of the light-emitting elements. The planar light source device according to any one of claims 1 to 7, wherein the light guide plate is made of one of glass, polymethyl methacrylate and polycarbonate. The planar light source device according to any one of claims 1 to 7, further comprising a diffuse reflection layer on the first side of the light guide plate. The planar light source device according to any one of claims 1 to 7, wherein the substrate further comprises a second surface opposite to the first surface, the planar light source device further comprising a second surface disposed on the substrate Reflective sheet on the surface. The planar light source device according to any one of claims 1 to 7, further comprising an optical film disposed on the second side of the light guide plate. The planar light source device of any one of claims 1 to 7, wherein the second side of the light guide plate forms a plurality of microstructures. The planar light source device of claim 12, wherein the microstructures are V-shaped, inverted V-shaped or curved.