TWI490562B - Backlight module using same - Google Patents

Description

Backlight module

The invention relates to a light guide plate and a backlight module, in particular to a light guide plate with uniform light emission, high brightness and excellent optical performance, and a backlight module using the light guide plate.

Due to its advantages of lightness, thinness, and low power consumption, liquid crystal displays are widely used in modern information equipment such as notebook computers, mobile phones, and personal digital assistants. Since the liquid crystal itself does not have a light-emitting property, it is required to provide a backlight module to realize the display function.

The existing backlight module includes a light source and a light guide plate. The light source is disposed relative to the light incident surface of the light guide plate. The light guide plate guides the light source to emit a light beam, and converts the point light source or the line light source into a surface light source.

Light-emitting diodes (LEDs) have been widely used in backlight modules in recent years due to their high brightness, long life, and anhydrous silver.

As shown in FIG. 1, in the backlight module 10 using an LED as a light source, due to the limitation of the divergence angle of the LED light source 13, the light column bright region 11 appears in the region of the light guide plate 17 near the LED light source 13, and the light guide plate 17 corresponds to the LED. A portion of the light source 13 passes through the light beam so that the shadow region 15 appears, which is referred to as a light column or a dark band phenomenon, respectively, which reduces the light uniformity of the light guide plate 17.

In view of this, it is necessary to provide a uniform light output, high brightness and excellent optical performance. a light guide plate and a backlight module using the light guide plate.

A light guide plate includes a light incident surface and a light exit surface connected to the light incident surface, wherein the light incident surface is provided with a plurality of V-shaped grooves recessed into the light incident surface, and between adjacent V-shaped slits There is a Fresnel lens, and the extending direction of the V-shaped slit is perpendicular to the light-emitting surface.

A backlight module includes a light guide plate and a light source, the light guide plate includes a light-emitting surface that is connected to the light-incident surface, the light source is disposed on the light-incident surface, and the light-incident surface is provided with a plurality of light-emitting surfaces a V-shaped groove recessed into the light incident surface, and a Fresnel lens between the adjacent V-shaped slits, the V-shaped slit extending in a direction perpendicular to the light-emitting surface.

Preferably, the V-shaped slit includes a first inclined surface and a second inclined surface intersecting the first inclined surface, and the angle between the first inclined surface and the second inclined surface is greater than equal 20 degrees and less than or equal to 120 degrees.

Compared with the prior art, the light-guiding plate of the embodiment of the present invention is provided with a plurality of V-shaped slots on the light-incident surface and a Fresnel lens between the adjacent V-shaped slots, and the light emitted by the light source is cut by the V-shaped After the groove and the Fresnel lens are refracted, the light guide plate enters the light guide plate at a large divergence angle, thereby reducing the dark band area and improving the light utilization rate, thereby increasing the light emission brightness and uniformity of the backlight module.

17, 20‧‧‧ light guide

13, 21‧‧‧ Light source

22‧‧‧Light guide plate

23‧‧‧Into the glossy surface

25‧‧‧ first side

26‧‧‧ second side

27‧‧‧Glossy

24‧‧‧V-cut

241‧‧‧ first slope

242‧‧‧Second slope

28‧‧‧ Fresnel lens

10‧‧‧Backlight module

11‧‧‧Light column

15‧‧‧Shaded area

1 is a schematic diagram of a backlight module in the prior art.

2 is a schematic diagram of a backlight module according to an embodiment of the present invention, including a light guide plate having a light incident surface.

The invention will now be described in further detail with reference to the accompanying drawings.

As shown in FIG. 2 , the backlight module 20 of the embodiment of the present invention includes a light source 21 and a light guide plate 22 . . The light source 21 is used to emit a light beam, and the light guide plate 22 guides the light source 21 to emit a light beam, and converts it into a surface light source.

The light guide plate 22 includes a light incident surface 23, a first side surface 25 connected to the light incident surface 23, a second side surface 26, and a light exit surface 27. The first side surface 25 and the second side surface 26 are located on both sides of the light incident surface 23. The light guide plate 22 may be in the shape of a flat plate or a wedge, and may be made of a synthetic resin material such as polycarbonate (PC) or polymethyl methacrylate (PMMA).

The light source 21 is disposed near the light incident surface 23, and the light emitted from the light source 21 enters the inside of the light guide plate 22 through the light incident surface 23, and is emitted by the light exit surface 27. The light source 21 is a point light source, which may be a light emitting diode or a bulb, etc., and may be configured with a plurality of different colors of light emitting diodes or bulbs to match the desired source color and brightness.

The light-incident surface 23 is disposed on a concave V-cut 24 having a first inclined surface 241 and a second inclined surface 242 intersecting between the first inclined surface 241 and the second inclined surface 242 The included angle is α, and there is a space between adjacent V-shaped slits 24. Wherein, α is greater than or equal to 20 degrees and less than and equal to 120 degrees; the pitches may be equal or may be in a gradient change, for example, increasing or decreasing from the first side 25 and the second side 26 toward the middle, respectively.

A Fresnel lens 28 is disposed between the adjacent V-shaped slits 24, which is a zigzag structure of concentric circles distributed, the depth of the zigzag structure being smaller than the depth of the V-shaped slit 24.

The light emitted by the light source 21 has a certain divergence angle, and is diffused and refracted by the V-shaped slit 24 and the Fresnel lens 28 to enter the light guide plate 22. The divergence angle of the light entering the light guide plate 22 is greatly increased, thereby reducing the dark band area. The brightness and uniformity of the backlight module 100 are improved.

Through experimental simulation, the brightness of the light guide plate 20 having the Fresnel lens 28 at the angle α of the V-shaped slit 24 is as follows:

As can be seen from the above table, the light-emitting luminance of the light guide plate 22 is made higher by providing V-shaped slits 24 of different angles on the light-incident surface 23.

In addition, those skilled in the art can make other changes in the spirit of the present invention. Of course, the changes made in accordance with the spirit of the present invention should be included in the scope of the present invention.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

20‧‧‧Light guide

21‧‧‧Light source

22‧‧‧Light guide plate

23‧‧‧Into the glossy surface

25‧‧‧ first side

26‧‧‧ second side

27‧‧‧Glossy

24‧‧‧V-cut

241‧‧‧ first slope

242‧‧‧Second slope

28‧‧‧ Fresnel lens

Claims (4)

A backlight module includes a light guide plate and a light source, the light guide plate includes a light-emitting surface that is connected to the light-incident surface, and the light source is disposed on the light-incident surface, and the improvement is: the light entering The surface is provided with a plurality of V-shaped grooves recessed into the light incident surface, and a Fresnel lens is arranged between the adjacent V-shaped slits, and the extending direction of the V-shaped slit is perpendicular to the light emitting surface, the V-shaped The grooving includes a first inclined surface and a second inclined surface intersecting the first inclined surface, and light emitted by the light source directly penetrates the first inclined surface, the second inclined surface, and the Fresnel lens into the guide Light board. The backlight module of claim 1, wherein the light source is a light emitting diode or a light bulb. The backlight module of claim 1, wherein an angle between the first inclined surface and the second inclined surface is greater than or equal to 20 degrees and less than or equal to 120 degrees. The optical module of claim 1, wherein: the spacing between adjacent V-shaped slots is equal or gradient.