CN102621618A - Light guide strip and light-emitting device - Google Patents

Abstract

The invention provides a light guide strip, comprising an upper surface and a light-out surface opposite to the upper surface, wherein the upper surface includes a main light-in surface, two inclined surfaces which form a relatively inclined connection with the main light-in surface, and two serrated surfaces which are connected with the two inclined surfaces respectively. The main light-in surface is a concave centrosymmetic curved surface, and each serrated surface is composed of a plurality of sawteeth which are arranged from central part outwards according to a geometric progression of the bottom width, with the common ratio of the geometric progression being q which is smaller than 1 and greater than 0, and the tooth-tips of the plurality of sawteeth are lower than the peak of the main light-in surface. The invention also provides a light-emitting device comprising such a light guide strip.

Description

Light guide strip and light emitting device

technical field

The invention relates to a light guide strip and a light-emitting device, in particular to a light guide strip and a light-emitting device suitable for a small-area light source.

Background technique

Generally speaking, the color temperature and brightness of the light emitted by each light emitting diode in the same batch of light emitting diodes are not the same due to the limitation of the process technology. When applied to a backlight module of a display, the difference in color temperature or brightness of each light-emitting diode will cause problems such as bright and dark areas or uneven colors on the display screen. In this case, it is necessary to use a light guide strip to adjust the light uniformity before entering the light guide plate. However, only a single light-emitting diode is usually used in the button light-emitting area or indicator light area, and the existing light guide strips cannot meet the light uniformity requirements of small-area light sources.

Contents of the invention

In view of this, it is necessary to provide a light guide strip and a light emitting device suitable for small-area light sources.

A light guide strip, which includes an upper surface and a light-emitting surface opposite to the upper surface. The upper surface includes a main light incident surface, two obliquely connected slopes relative to the main light incident surface, and two sawtooth surfaces respectively connected to the two slopes; the main light incident surface is a concave centrally symmetrical curved surface , each sawtooth face is formed by a plurality of sawtooths, the base widths of the multiple sawtooths are arranged in a geometric sequence from the center outward, and the common ratio of the geometric sequence is q, q is less than 1 and greater than 0, each The tips of the plurality of sawtooths are not higher than the highest point of the main light incident surface.

A light-emitting device, which includes a point light source and a light-guiding strip, the light-guiding strip includes an upper surface and a light-emitting surface opposite to the upper surface. The upper surface includes a main light incident surface, two obliquely connected slopes relative to the main light incident surface, and two sawtooth surfaces respectively connected to the two slopes; the main light incident surface is a concave centrally symmetrical curved surface , each sawtooth face is formed by a plurality of sawtooths, the bottom widths of the multiple sawtooths are arranged in a geometric sequence from the center outward, and the common ratio of the geometric sequence is q, q is less than 1 and greater than 0, the point The light source is facing the main light incident surface, and the tip of each of the plurality of sawtooth is not higher than the highest point of the main light incident surface.

Compared with the prior art, the light guide strip provided by the present invention is suitable for use with small-area light sources such as display indicator lights and keyboard indicator lights. The serrated surface provided by it can improve the uniformity of light output and avoid dark spots in the light output area. The light-emitting device is used in occasions that require a small-area light source, and the light is uniform.

Description of drawings

FIG. 1 is a schematic perspective view of a three-dimensional structure of a light guide strip provided by an embodiment of the present invention.

Fig. 2 is a schematic diagram of an optical path of a light emitting device provided by an embodiment of the present invention.

Description of main component symbols

Lighting device 100

Point Light 10

Light guide strip 20

Upper surface 22

Main incident light surface 220

Bevel 222

Serrated surface 224

Serrated 30

Light emitting surface 24

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

Referring to FIG. 1 and FIG. 2 , the light emitting device 100 provided by the embodiment of the present invention includes a point light source 10 and a light guide strip 20 . The light emitting area of the point light source 10 is small, for example, the point light source 10 only has one or two LEDs. The light guide strip 20 includes an upper surface 22 and a light emitting surface 24 opposite to the upper surface 22 . In this embodiment, the length direction of the light guide strip 20 is larger or much larger than the width direction.

The upper surface 22 includes a main light incident surface 220 , two inclined surfaces 222 inclined relative to the main light incident surface 220 , and two serrated surfaces 224 connected to the inclined surfaces 222 . The point light source 10 is directly on the main light incident surface 220 , that is, the light emitted by the point light source 10 is basically incident on the main light incident surface 220 , and is basically obliquely incident on the inclined surface 222 and the serrated surface 224 . The area of the main light incident surface 220 is determined according to the light divergence angle of the point light source 10 and the distance from the point light source 10 to the center of the main light incident surface 220 .

The main light incident surface 220 is a concave central symmetrical curved surface. In this embodiment, the main light incident surface 220 is a concave cylindrical surface. In other embodiments, the main light incident surface 220 can also be a concave curved surface of other shapes, such as a paraboloid, a spherical surface, and the like. The two inclined surfaces 222 are respectively connected to two opposite ends of the main light incident surface 220 and extend outward. The two slopes 222 are symmetrical to the center of the main light incident surface 220 .

The two sawtooth surfaces 224 are symmetrical to the center of the main light incident surface 220 .

Each sawtooth surface 224 includes a plurality of sawtooth 30 , and each inclined surface 222 connects the main light incident surface 220 and the serration 30 closest to the main light incident surface 220 .

In this embodiment, the cross section of each sawtooth 30 is similar to a right-angled triangle, and the right-angled side is closer to the center of the light guide strip 20 than the hypotenuse. The tip of each sawtooth 30 is equal to or lower than the highest point of the main light incident surface 220 .

A plurality of saw teeth 30 on the same side form a group. In the same group of saw teeth, the width of each saw tooth 30 tooth bottom is arranged in a geometric sequence from the center outward, and the common ratio of the geometric sequence is q, and q is less than 1 and It is greater than 0, that is, from the center to the outer edge, the sawtooth 30 becomes smaller and smaller. The smaller and smaller sawtooth 30 is beneficial to increase the reflection and refraction of the light, so as to make the light more uniform. For example, if the tooth bottom width of one sawtooth 30 is 1mm, and q is 1/5, then the width of the tooth bottom of the second sawtooth adjacent to the sawtooth 30 is 0.2mm, and so on.

The light emitted by the point light source 10 is emitted from the light emitting surface 24 . In this embodiment, the light-emitting surface 24 is a plane, and the emitted light is substantially perpendicular to the light-emitting surface 24 .

Specifically, the point light source 10 is a light emitting diode, and the bottom width of the tooth 30 closest to the main light incident surface 220 is approximately equal to q times the length of the light emitting surface of the light emitting diode. For example, if q is calculated as 1/5, if the length of the light-emitting surface of the LED is 5 mm, the width of the tooth bottom of the sawtooth 30 closest to the main light-incident surface 220 is 1 mm.

Since the main light incident surface 220 of the light guide strip 20 basically only receives light from the point light source 10 in the almost normal direction, and the remaining light enters the light guide strip 20 through the inclined surface 222 and the serrated surface 224, thereby passing through After being reflected and refracted by the set of sawtooths 30, the emitted light becomes uniform, thereby achieving the purpose of improving the light uniformity of the small-area light source.

The length of the light guide strip 20 does not need to be too long. Preferably, the width of the upper surface 22 along its length direction is greater than or substantially equal to twice the width of the divergence angle of the point light source 10 so as to receive all the light emitted by the point light source 10 as much as possible.

The light emitting device 100 provided in this embodiment includes a pair of point light sources 10 and light guide strips 20, and multiple pairs of point light sources 10 and light guide strips 20 can also be designed according to needs, and multiple light guide strips 20 can be connected or separated. .

The light guide strip provided by the invention is suitable for use with small-area light sources such as display indicator lights and keyboard indicator lights. The serrated surface provided by it can improve the uniformity of light output and avoid dark spots in the light output area. For small-area light sources, the light output is uniform.

It can be understood that those skilled in the art can also make other changes within the spirit of the present invention, which should be included within the scope of the present invention.

Claims (10)

1. A light guide strip, comprising: An upper surface, including a main light incident surface, two obliquely connected oblique surfaces relative to the main light incident surface, and two sawtooth surfaces respectively connected to the two inclined surfaces; the main light incident surface is a concave central symmetry A curved surface, each sawtooth surface is formed by a plurality of sawtooths, the base widths of the multiple sawtooths are arranged in a geometric sequence from the center to the outside, and the common ratio of the geometric sequence is q, q is less than 1 and greater than 0, each none of the plurality of serrations is higher than the highest point of the main light incident surface; and A light-emitting surface opposite to the upper surface. 2 . The light guide strip according to claim 1 , wherein the two inclined surfaces are respectively connected to two opposite ends of the main light incident surface and extend outward. 3 . 3 . The light guide strip according to claim 1 , wherein the two slopes are symmetrical to the center of the main light incident surface, and the two sawtooth surfaces are symmetrical to the center of the main light incident surface. 4. The light guide strip according to claim 1, wherein the light emitting surface is a plane. 5. The light guide strip according to claim 4, wherein the light emitted from the light-emitting surface is substantially perpendicular to the light-emitting surface. 6. A light emitting device comprising: a point light source; A light guide strip comprising: An upper surface, including a main light incident surface, two obliquely connected oblique surfaces relative to the main light incident surface, and two sawtooth surfaces respectively connected to the two inclined surfaces; the main light incident surface is a concave central symmetry A curved surface, each sawtooth surface is formed by a plurality of sawtooths, the base widths of the multiple sawtooths are arranged in a geometric sequence from the center to the outside, and the common ratio of the geometric sequence is q, q is less than 1 and greater than 0, each none of the teeth tips of the plurality of serrations is higher than the highest point of the main light incident surface on which the point light source is directed; and A light-emitting surface opposite to the upper surface. 7. The light-emitting device according to claim 6, wherein the point light source is a single light-emitting diode, and the tooth bottom width of the sawtooth closest to the main light incident surface is equal to q times the length of the light-emitting surface of the light-emitting diode . 8. The light emitting device according to claim 6, wherein the width of the upper surface along its length direction is substantially equal to or greater than twice the width of the divergence angle of the point light source. 9 . The light emitting device according to claim 6 , wherein the light emitting device comprises a plurality of point light sources and a plurality of light guide strips, and the plurality of point light sources correspond to the plurality of light guide strips one by one. 10. The light emitting device according to claim 9, wherein two adjacent light guide strips are separated from each other.

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