TWI497171B - Backlight module - Google Patents

Description

Backlight module

The invention relates to a backlight module, in particular to a backlight module with a light reflecting member.

With the advancement of technology, the technology of display has been continuously developed, and the thin flat panel display (FPD) gradually replaces the traditional thick cathode cathode tube display (CRT). Common flat panel displays include Plasma Display Panels (PDPs) and Liquid Crystal Displays (LCDs), which can be widely used in personal digital assistants, notebook computers, mobile phones and televisions.

Taking a liquid crystal display as an example, the liquid crystal display includes a liquid crystal panel and a backlight module. The liquid crystal panel is composed of two transparent substrates and a liquid crystal layer disposed between the two transparent substrates, and the backlight module is used to provide a light source required for the liquid crystal panel to achieve the display effect of the liquid crystal display. In general, the backlight module can be divided into two types: Side Incident Type and Direct Type. The side-lit backlight module is usually used in a small-sized liquid crystal display. Direct-lit backlight modules are commonly used in larger-sized liquid crystal displays.

Since liquid crystal displays have been developed toward large sizes, most of them use a direct type backlight module. Therefore, a direct type backlight module will be exemplified below. In the direct type backlight module, a plurality of light emitting diodes are arranged in an array, and a light emitting surface of the light emitting diode faces the diffusion plate and the liquid crystal panel. The diffuser plate converts the light beam of the light emitting diode into a surface light source and then illuminates the liquid crystal panel. Of course However, since the light-emitting diode is a light source having high directivity characteristics, the light intensity at the near-point light source is often greater than the light intensity at the far-point light source, resulting in poor uniformity of the backlight. In order to improve the uniformity of the backlight, the manufacturer generally increases the number of light-emitting diodes of the direct-lit backlight module. However, even if the number of light-emitting diodes is greatly increased, the uniformity of the surface light source cannot be effectively improved, and the production cost and the power consumption of the direct-type backlight module are increased.

The invention provides a backlight module, which improves the uniformity of the backlight module and reduces the production cost and power consumption of the backlight module.

The backlight module disclosed in the present invention comprises a substrate, a light source and a light reflecting member. The light source is disposed on the substrate. The light source has a light exit surface. The light reflecting member is disposed on the substrate and disposed around the light source. The light reflecting member has a first annular reflecting surface and a second annular reflecting surface. The light source is between the first annular reflective surface and the substrate, and the first annular reflective surface faces the light exit surface. The second annular reflecting surface surrounds the light source and faces the first annular reflecting surface.

According to the backlight module disclosed in the present invention, the first annular reflecting surface covers the arrangement relationship between the light source and the second annular reflecting surface surrounding the light source to expand the light pointing angle of each light source, thereby improving the uniformity of the backlight module.

In addition, the light directing angle of each light source is increased, so that the spacing of the light sources can be enlarged to effectively reduce the number of light sources required, thereby reducing the cost of the backlight module.

Furthermore, the first annular reflecting surface and the second annular reflecting surface of the light reflecting member re-reflect the light originally radiated to the periphery of the light source to the diffusing plate, thereby increasing the light intensity of each light source to the diffusing plate. As a result, the number of light sources required for the backlight module of the embodiment can be relatively reduced, thereby reducing the cost of the backlight module and the power consumption of the backlight module.

The above description of the present invention and the following description of the embodiments are intended to illustrate and explain the principles of the invention, and to provide a further explanation of the scope of the invention.

10‧‧‧Backlight module

100‧‧‧Substrate

110‧‧‧ third annular reflecting surface

200‧‧‧Light source

210‧‧‧Glossy surface

300‧‧‧Light reflectors

310‧‧‧ Coverage

311‧‧‧First annular reflecting surface

312‧‧‧ bottom

313‧‧‧ cone apex

320‧‧‧ Surrounding

321‧‧‧Second annular reflecting surface

330‧‧‧Connecting Department

400‧‧‧Diffuser

1 is a partial perspective view of a backlight module according to a first embodiment of the present invention without a diffuser plate.

Fig. 2 is a perspective view showing the light reflecting member of Fig. 1.

Fig. 3 is a schematic cross-sectional view showing the backlight module of Fig. 1 provided with a diffusing plate and taken along line 3-3.

Fig. 4 is a schematic view showing the optical simulation of the light reflecting member without the second annular reflecting surface.

Fig. 5 is a schematic view showing the optical simulation of a light reflecting member made of a plastic material.

Fig. 6 is a schematic diagram showing the optical intensity simulation of the light reflecting member made of the plastic material of the backlight module having the second annular reflecting surface and the backlight module without the second annular reflecting surface.

Fig. 7 is a perspective view showing a light reflecting member according to a second embodiment of the present invention.

Fig. 8 is a schematic view showing the optical simulation of a light reflecting member made of a metal material.

FIG. 9A is a partial cross-sectional view showing a backlight module according to a third embodiment of the present invention.

FIG. 9B is a partial cross-sectional view showing a backlight module according to a fourth embodiment of the present invention.

9C is a partial cross-sectional view showing a backlight module according to a fifth embodiment of the present invention.

FIG. 10A is a partial cross-sectional view showing a backlight module according to a sixth embodiment of the present invention.

FIG. 10B is a partial cross-sectional view showing a backlight module according to a seventh embodiment of the present invention.

10C is a partial cross-sectional view showing a backlight module according to an eighth embodiment of the present invention.

Please refer to Figures 1 to 3. 1 is a partial perspective view of a backlight module according to a first embodiment of the present invention without a diffuser plate. Fig. 2 is a perspective view showing the light reflecting member of Fig. 1. Fig. 3 is a schematic cross-sectional view showing the backlight module of Fig. 1 provided with a diffusing plate and taken along line 3-3.

The backlight module 10 of the embodiment is configured to generate a backlight and direct the backlight to a liquid crystal panel (not shown). The backlight module 10 includes a substrate 100, a light source 200, and a light reflecting member 300.

The substrate 100 is, for example, a printed circuit board or a flexible printed circuit board.

The light source 200 is disposed on the substrate 100 and has a light emitting surface 210 for emitting a light beam away from the substrate 100. The light exit surface 210 has a central vertical normal N. The center vertical normal N is perpendicular to the light exit surface 210 and passes through the center point of the light exit surface 210. The light source 200 is, for example, a light emitting diode.

The light reflecting member 300 includes a covering portion 310, a surrounding portion 320, and an engaging portion 330. The cover portion 310 covers the light source 200, in other words, the light source 200 is interposed between the cover portion 310 and the substrate 100. In the present embodiment, the outer shape of the covering portion 310 is a conical shape, and the covering portion 310 has a first annular reflecting surface 311, a bottom surface 312, and a tapered apex 313. The bottom surface 312 and the tapered apex 313 are located on opposite sides of the cover portion 310, and the tapered apex 313 is closer to the light exit surface 210 of the light source 200 than the bottom surface 312. One side of the first annular reflecting surface 311 is connected to the edge of the bottom surface 312, and the other side thereof is connected to the tapered vertex 313 to form a conical shape, that is, the tapered vertex 313 is the intersection of the first annular reflecting surface 311. . The first annular reflecting surface 311 faces the light emitting surface 210 of the light source 200, and the center vertical normal line N of the light emitting surface 210 passes through the tapered vertex 313. The first annular reflecting surface 311 is perpendicular to the center The normal line N has a first angle θ1 of approximately 60 degrees to 87.5 degrees.

Further, the ratio of the diameter D1 of the bottom surface 312 to the distance D2 between the tapered apex 313 of the covering portion 310 and the light exiting surface 210 is about 4 to 1. For example, when the pitch of the tapered apex 313 and the light exiting surface 210 is 1 millimeter (mm), the diameter of the bottom surface 312 is about 4 millimeters (mm). In addition, the ratio of the width D4 of the light-emitting surface 210 of the light source 200 to the distance D2 between the tapered apex 313 and the light-emitting surface 210 of the cover portion 310 ranges from about 2 to 1 to 2 to 7.

The surrounding portion 320 is disposed on the substrate 100. The surrounding portion 320 has a second annular reflecting surface 321 . The second annular reflecting surface 321 surrounds the light source 200 and faces the first annular reflecting surface 311. The second annular reflecting surface 321 and the central vertical normal line N have a second angle θ2 of approximately 60 degrees to 87 degrees. The ratio of the diameter D3 of the outer edge of the second annular reflecting surface 321 to the diameter D1 of the bottom surface 312 of the covering portion 310 is about 2 to 1.

The engaging portion 330 is connected between the surrounding portion 320 and the covering portion 310 and maintains a predetermined gap between the covering portion 310 and the surrounding portion 320. The purpose of the engaging portion 330 is to enhance the structural strength of the light reflecting member 300, and to prevent the covering portion 310 from being shaken by an external force. In this embodiment, the number of the engaging portions 330 is three, but not limited thereto. In other embodiments, the number of the engaging portions 330 may be the same as the supporting strength of the engaging portion 310 is sufficiently strong. One or two or more.

In the present embodiment, the light reflecting member 300 is formed by plastic injection molding, and the material of the light reflecting member 300 is selected from a plastic material having a reflectance of 0.75 to 0.9. That is, the material of the first annular reflecting surface 311 and the second annular reflecting surface 321 have a reflectance of between 0.75 and 0.9.

In this embodiment, the first angle θ1 between the first annular reflecting surface 311 and the central vertical normal line N and the second angle θ between the second annular reflecting surface 321 and the central vertical normal line N 2 both maintain the same angle relationship. Further, in the cross-sectional view of the backlight module 10 (as shown in FIG. 3 ), the first annular reflective surface 311 and the second annular reflective surface 321 are straight lines formed in the cross-sectional view, and the first ring is The reflective surface 311 and the second annular reflective surface 321 are arranged in parallel.

In this embodiment and other embodiments, the substrate 100 has a third annular reflecting surface 110 between the light source 200 and the second annular surrounding portion 321 to reflect light incident on the region to the liquid crystal panel (not Painted). In the embodiment, the third annular reflecting surface 110 is parallel to the substrate 100.

The colors of the first annular reflecting surface 311, the second annular reflecting surface 321 and the third annular reflecting surface 110 are white or silver (mirror).

In this embodiment and other embodiments, the backlight module 10 further includes a diffusion plate 400. The light source 200 and the light reflecting member 300 are interposed between the substrate 100 and the diffusion plate.

Next, please refer to Table 1 and Figures 4 to 6. Fig. 4 is a schematic view showing the optical simulation of the light reflecting member without the second annular reflecting surface. Fig. 5 is a schematic view showing the optical simulation of a light reflecting member made of a plastic material. FIG. 6 is a schematic diagram showing the optical intensity simulation of the backlight module having the first annular reflecting surface and the second annular reflecting surface of the light reflecting member and the backlight module having only the first annular reflecting surface of the light reflecting member.

First, the case where the light reflecting member 300 has only the first annular reflecting surface 311 will be described first. As shown in FIG. 4 and Table 1, when the light reflecting member 300 is simulated by the backlight module having only the first annular reflecting surface 311, the light pointing angle of the backlight module 10 is simulated to be 50 degrees, and the backlight mode is The uniformity of group 10 was 76.27 percent. Here, the light pointing angle is the degree of light concentration, and the larger the light pointing angle, the more the light beam emitted from the light source 200 is diffused. The smaller the light pointing angle, the more concentrated the light beam emitted by the light source 200.

Next, when the light reflecting member 300 has both the first annular reflecting surface 311 and the second annular reflecting surface 321 , and the first angle θ1 between the first annular reflecting surface 311 and the central vertical normal line N is between 60 degrees and 87.5 And the second angle θ2 between the second annular reflecting surface 321 and the central vertical normal line N is between 60 degrees and 87 degrees, and the light pointing angle of the backlight module 10 is expanded to 75 degrees (more than 50 degrees). ), and the uniformity of the backlight module 10 is increased to 91.37 percent (greater than 76.27 percent). According to the above simulation data, the light reflecting member 300 made of plastic material has the first annular reflecting surface 311 and the second annular reflecting surface 321 at the same time, which will greatly improve the uniformity of the backlight module 10.

Furthermore, as shown in FIG. 6, the backlight module 10 of the present embodiment re-reflects the light originally radiated to the periphery of the light source 200 to the diffusion plate 400 through the light reflecting member 300, so that the backlight module 10 of the embodiment The light intensity is greater than the light intensity of the backlight module in which the second annular light reflecting surface 321 is not disposed. As a result, the number of the light sources 200 required by the backlight module 10 of the present embodiment can be relatively reduced, thereby reducing the cost of the backlight module 10.

The light reflecting member 300 is made of a plastic material, but is not limited thereto. In other embodiments, the light reflecting member 300 may also be made of metal. Please refer to Figure 7. Fig. 7 is a perspective view showing a light reflecting member according to a second embodiment of the present invention. Different from the above embodiment, the light reflecting member 300 of the present embodiment is made of a group of metal materials having a reflectance of 0.85 to 0.99.

Next, please refer to Table 2 and Figure 8. Fig. 8 is a schematic view showing the optical simulation of a light reflecting member made of a metal material.

When the light reflecting member 300 is made of a metal material having a reflectance of 0.85 to 0.99, and the first angle θ1 between the first annular reflecting surface 311 and the center vertical normal line N is between 60 degrees and 87.5 degrees, and the second ring shape When the second angle θ2 between the reflecting surface 321 and the central vertical normal line N is between 60 degrees and 87 degrees, the light pointing angle of each light source 200 is expanded to be 63 degrees (more than 50 degrees), and the backlight module 10 is The uniformity is increased to 78.52% (greater than 76.27%). According to the above simulation data, the light reflecting member 300 made of a metal material has both the first annular reflecting surface 311 and the second annular reflecting surface 321 , which will greatly improve the uniformity of the backlight module 10 .

In the above embodiment, the first angle θ1 is exemplified by 60 degrees to 87.5 degrees, and the second angle θ2 is exemplified by 60 degrees to 87 degrees, but is not limited thereto. In other embodiments. In the middle, the angle between the first angle θ1 plus the second angle θ2 may be between 225 degrees and 235 degrees.

The first angle θ1 between the first annular reflecting surface 311 and the central vertical normal line N and the second angle θ2 between the second annular reflecting surface 321 and the central vertical normal line N are all in the same angular relationship, but For example, in other embodiments, the first angle θ1 between the first annular reflection surface 311 and the central vertical normal line N and the second angle θ2 between the second annular reflection surface 321 and the center vertical normal line N may also be used. A plurality of different angular relationships are maintained, that is, the line segment formed by the first annular reflective surface 311 or the second annular reflective surface 321 in the cross-sectional view may be a curved line or a plurality of line segments having different slopes.

For example, please refer to Figures 9A through 10C. FIG. 9A is a partial cross-sectional view showing a backlight module according to a third embodiment of the present invention. FIG. 9B is a partial cross-sectional view showing a backlight module according to a fourth embodiment of the present invention. 9C is a partial cross-sectional view showing a backlight module according to a fifth embodiment of the present invention. FIG. 10A is a partial cross-sectional view showing a backlight module according to a sixth embodiment of the present invention. FIG. 10B is a partial cross-sectional view showing a backlight module according to a seventh embodiment of the present invention. 10C is a partial cross-sectional view showing a backlight module according to an eighth embodiment of the present invention.

As shown in FIG. 9A, the line segment formed by the outer edge to the tapered apex 313 in the cross-sectional view of the first annular reflecting surface 311 of the present embodiment is a straight line segment, and the second annular reflecting surface 321 is in the cross-sectional view. The line segment formed by the outer edge to the inner edge is at least two connected straight lines of different slopes. This embodiment takes two connected straight lines as an example. That is, the second annular reflecting surface 321 is in section The two straight lines formed in the plan view are respectively at an angle θ21, θ22 with the center vertical normal N.

As shown in FIG. 9B, the line segment formed by the outer edge to the tapered apex 313 in the cross-sectional view of the first annular reflecting surface 311 of the present embodiment is a straight line segment, and the second annular reflecting surface 321 is in the cross-sectional view. The line segments formed by the outer edge to the inner edge are curved and respectively maintain a plurality of angles with the central vertical normal N. In the present embodiment, the curve is convex from the surrounding portion 320 toward the covering portion 310.

As shown in FIG. 9C, the line segment formed by the outer edge to the tapered apex 313 in the cross-sectional view of the first annular reflecting surface 311 of the present embodiment is a straight line segment, and the second annular reflecting surface 321 is in the cross-sectional view. The line segments formed by the outer edge to the inner edge are curved and respectively maintain a plurality of angles with the central vertical normal N. In the present embodiment, the curve is recessed by the surrounding portion 320 toward the substrate 100.

In the embodiment of the above-mentioned 9A to 9C, the line segment formed by the outer edge to the tapered vertex 313 in the cross-sectional view is a straight line segment, but not limited thereto. In other embodiments, the line segment formed by the outer ring to the tapered apex 313 in the cross-sectional view of the first annular reflecting surface 311 may also be a plurality of connected straight lines of curved segments or different slopes.

As shown in FIG. 10A, the line segment formed by the outer edge to the tapered apex 313 in the cross-sectional view of the first annular reflecting surface 311 of the present embodiment is at least two connected straight lines of different slopes, and this embodiment is Take the two straight lines connected as an example. The line segment formed by the outer edge to the inner edge in the cross-sectional view of the second annular reflecting surface 321 is a straight line segment.

As shown in FIG. 10B, the first annular reflecting surface 311 of the present embodiment has a line segment formed by the outer edge to the tapered apex 313 in a cross-sectional view as a curve and respectively maintains a plurality of angles with the central vertical normal N. In the present embodiment, the curve is convex from the covering portion 310 toward the surrounding portion 320. The line segment formed by the outer edge to the inner edge of the second annular reflecting surface 321 in the cross-sectional view is a straight line segment.

As shown in FIG. 10C, the first annular reflecting surface 311 of the present embodiment has a line segment formed by the outer edge to the tapered apex 313 in a cross-sectional view as a curve and respectively maintains a plurality of angles with the central vertical normal N. In the present embodiment, the curve is recessed by the covering portion 310 toward the diffusion plate 400. The line segment formed by the outer edge to the inner edge in the cross-sectional view of the second annular reflecting surface 321 is a straight line segment.

In the embodiment of the above-mentioned 10A to 10C, the line segment formed by the outer edge to the inner edge of the second annular reflecting surface 321 is a straight line segment, but is not limited thereto. In other embodiments. The line segment formed by the outer edge to the inner edge in the cross-sectional view of the second annular reflecting surface 321 may also be a plurality of connected straight lines of curved segments or different slopes.

According to the backlight module disclosed in the present invention, the first annular reflecting surface covers the arrangement relationship between the light source and the second annular reflecting surface surrounding the light source, and the angle relationship between the first annular reflecting surface and the central vertical normal line and the second The angle between the annular reflecting surface and the center perpendicular normal line increases the light pointing angle of each light source, thereby improving the uniformity of the backlight module.

Furthermore, the first annular reflecting surface and the second annular reflecting surface of the light reflecting member re-reflect the light originally radiated to the periphery of the light source to the diffusing plate, thereby increasing the light intensity of each light source to the diffusing plate. As a result, the number of light sources required for the backlight module of the embodiment can be relatively reduced, thereby reducing the cost of the backlight module and the power consumption of the backlight module.

Although the embodiments of the present invention are disclosed above, it is not intended to limit the present invention, and those skilled in the art, regardless of the spirit and scope of the present invention, the shapes, configurations, and features described in the scope of the present application. And the number of modifications may be made, and the scope of patent protection of the present invention shall be determined by the scope of the patent application attached to the specification.

100‧‧‧Substrate

110‧‧‧ third annular reflecting surface

200‧‧‧Light source

210‧‧‧Glossy surface

300‧‧‧Light reflectors

310‧‧‧ Coverage

311‧‧‧First annular reflecting surface

312‧‧‧ bottom

313‧‧‧ cone apex

320‧‧‧ Surrounding

321‧‧‧Second annular reflecting surface

330‧‧‧Connecting Department

400‧‧‧Diffuser

Claims (17)

A backlight module includes: a substrate; a light source disposed on the substrate, the light source having a light emitting surface; and a light reflecting member disposed on the substrate and disposed around the light source, the light reflecting member having a first An annular reflecting surface and a second annular reflecting surface, the light source is interposed between the first annular reflecting surface and the substrate, and the first annular reflecting surface faces the light emitting surface, and the second annular reflecting surface surrounds The light source faces the first annular reflecting surface; wherein the light exiting mask has a central vertical normal, the first annular reflecting surface has a first angle with the central vertical normal, and the second annular reflection The surface has a second angle between the vertical normal line and the center, and the angle between the first angle and the second angle is between 225 degrees and 235 degrees. The backlight module of claim 1, wherein the light reflecting member comprises a covering portion having the first annular reflecting surface and a surrounding portion having the second annular reflecting surface, the surrounding portion is disposed on the substrate and Surrounding the light source, the cover portion is coupled to the surrounding portion and covers the light source, and a gap is maintained between the cover portion and the surrounding portion. The backlight module of claim 2, wherein the light reflecting member further comprises at least one engaging portion connected between the covering portion and the surrounding portion to maintain the gap between the covering portion and the surrounding portion. The backlight module of claim 2, wherein the light-emitting mask of the light source has a central vertical normal line, and the cover portion has a conical shape, and the cover portion has a tapered vertex for the first circular reflection The intersection of the faces, and the center vertical normal passes through the tapered apex. The backlight module of claim 4, wherein the covering portion has a bottom surface connecting the first annular reflecting surface, a diameter of the bottom surface and a ratio of a distance between the tapered vertex of the covering portion and the light emitting surface It is 4 to 1. The backlight module of claim 5, wherein a ratio of a diameter of an outer edge of the second annular reflecting surface to a diameter of the bottom surface is 2 to 1. The backlight module of claim 4, wherein a ratio of a width of the light-emitting surface to a distance between the tapered apex of the covering portion and the light-emitting surface ranges from 2 to 1 to 2 to 7. The backlight module of claim 4, wherein an outer edge of the first annular reflecting surface to the tapered apex maintains the same angular relationship with the central normal. The backlight module of claim 4, wherein an outer edge to an inner edge of the second annular reflecting surface maintains the same angular relationship with the central vertical normal. The backlight module of claim 4, wherein one of the outer edges of the first annular reflecting surface has a plurality of different angular relationships from the central vertex of the tapered apex. The backlight module of claim 10, wherein the cross-sectional contour of the first annular reflecting surface from the outer edge to the tapered vertex is a curved line or a plurality of line segments having different slopes. The backlight module of claim 4, wherein one of the outer edges of the second annular reflecting surface to an inner edge has a plurality of different angular relationships with the central normal. The backlight module of claim 12, wherein the cross-sectional contour of the second annular reflecting surface from the outer edge to the inner edge is a curved line or a plurality of line segments having different slopes. The backlight module of claim 1, wherein the substrate has a third annular reflecting surface between the light source and the second annular surrounding portion and surrounding the light source. The backlight module of claim 1, wherein the first annular reflecting surface is perpendicular to the center The included angle is between 60 degrees and 87.5 degrees, and the angle between the second annular reflecting surface and the center perpendicular is between 60 degrees and 87 degrees. The backlight module of claim 1, further comprising a diffusing plate, the light source and the light reflecting member being interposed between the substrate and the diffusing plate. The backlight module of claim 1, wherein the material of the first annular reflecting surface and the material of the second annular reflecting surface are selected from a plastic material having a reflectance of 0.75 to 0.9 and a reflectance of 0.85 to 0.99. a group of metallic materials.