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CN-117310864-B - Light guide element and backlight module

CN117310864BCN 117310864 BCN117310864 BCN 117310864BCN-117310864-B

Abstract

The invention provides a light guide element, which comprises a main body and an optical microstructure recessed into the bottom surface of the main body. The optical microstructure comprises a light-facing surface and a light-backing surface which face and face away from the light-entering surface of the main body respectively. The light-receiving surface has a first cross-section on a first quasi-plane perpendicular to the light-entering surface and parallel to the bottom surface, and has a second cross-section on a second quasi-plane parallel to the light-entering surface and perpendicular to the bottom surface. The first quasi-arc line passes through a first vertex close to the light incident surface and a plurality of first endpoints far away from the light incident surface in the first intercept line. The second quasi-arc line passes through a second vertex close to the light-emitting surface and a plurality of second endpoints far away from the light-emitting surface in the second intercept line. The radius of curvature R xz of the second quasi-arc is greater than the radius of curvature R xy of the first quasi-arc. The width W x of the optical microstructure in a first direction parallel to the light-in surface and the bottom surface is greater than the width W y in a second direction perpendicular to the light-in surface and the first direction and parallel to the bottom surface. The light guide element and the backlight module with the light guide element can improve the uniformity of light emission.

Inventors

  • LIN GUANTING
  • ZHOU MINJUN
  • FANG YUFU

Assignees

  • 台湾扬昕股份有限公司

Dates

Publication Date
20260505
Application Date
20220622

Claims (17)

  1. 1. A light guiding element comprising a body and an optical microstructure, wherein The main body comprises a bottom surface, a light emitting surface and a light entering surface, wherein The light-emitting surface is arranged opposite to the bottom surface, and The light incident surface is connected between the light emergent surface and the bottom surface, and The optical microstructure is recessed in the bottom surface of the main body, wherein the optical microstructure comprises a light-receiving surface and a light-receiving surface, wherein The light incident surface faces the light incident surface, and The backlight surface is opposite to the light incident surface, and the light incident surface is positioned between the backlight surface and the light incident surface; The first quasi-plane is perpendicular to the light incident surface and parallel to the bottom surface, the light incident surface is provided with a first cross section line on the first quasi-plane, the first cross section line is provided with a first vertex close to the light incident surface and a plurality of first endpoints far away from the light incident surface and respectively positioned at two sides of the first vertex, a first quasi-arc line passes through the first vertex and the plurality of first endpoints, the first quasi-arc line is provided with a curvature radius R xy , and R xy is 15 mu m <60 mu m; The second quasi-plane is parallel to the light incident surface and perpendicular to the bottom surface, the light incident surface is provided with a second truncated line on the second quasi-plane, the second truncated line is provided with a second vertex close to the light emergent surface and a plurality of second endpoints far away from the light emergent surface and respectively positioned at two sides of the second vertex, a second quasi-arc line passes through the second vertex and the second endpoints, the second quasi-arc line is provided with a curvature radius R xz , and R xz is 30 μm; the radius of curvature R xz of the second quasi-arc is greater than the radius of curvature R xy of the first quasi-arc; The optical microstructure has a first width W x in a first direction parallel to the light-in surface and the bottom surface, the optical microstructure has a second width W y in a second direction perpendicular to the light-in surface and the first direction and parallel to the bottom surface, and the first width W x is greater than the second width W y .
  2. 2. The light guide element of claim 1, wherein the light-facing surface and the bottom surface have a first interface that is part of a first quasi-elliptical curve having a first major axis in the second direction and a first minor axis in the first direction.
  3. 3. The light guide element of claim 2, wherein a half-axis length of the first major axis of the first pseudo-elliptic curve is a, b is a >1.5b.
  4. 4. The light guide element of claim 2, wherein the backlight surface and the bottom surface have a second interface, and the second interface is a portion of a second pseudo-elliptic curve.
  5. 5. The light guide element according to claim 4, wherein a half-axis length of the first major axis of the first pseudo-elliptic curve is a, the second pseudo-elliptic curve has a first axis and a second axis in the first direction and the second direction, respectively, a half-axis length of the second axis of the second pseudo-elliptic curve is c, and a > c.
  6. 6. The light guide element of claim 1, wherein the light-facing surface comprises a sub-plane and a plurality of side sub-arcs, wherein The sub-plane is inclined relative to the light incident surface and the bottom surface, and The plurality of side sub-cambered surfaces are respectively connected with two sides of the sub-plane, wherein each of the plurality of side sub-cambered surfaces is bent in the first direction and the second direction.
  7. 7. The light guide element of claim 6, wherein the sub-plane and the plurality of side sub-curved surfaces meet at two edge lines, respectively, the plurality of edge lines meet the backlight surface at a plurality of intersection points, the plurality of intersection points have a distance S in the first direction, and S <2W x /3.
  8. 8. The light guide element of claim 1, wherein the light-facing surface is a continuous arc surface.
  9. 9. The light guide element of claim 1, wherein the light-facing surface comprises a plurality of first sub-surfaces and a plurality of second sub-surfaces, wherein The first sub-surfaces are inclined relative to the light incident surface and the bottom surface, wherein the first sub-surfaces are connected with each other, the third quasi-plane is perpendicular to the light incident surface and the bottom surface, and the inclination directions of the first sub-surfaces relative to the third quasi-plane are opposite, and The second sub-surfaces are respectively located at two sides of the first sub-surfaces, wherein the first sub-surfaces intersect at a ridge line, the ridge line is located on the third quasi-plane, the second sub-surfaces incline relative to the bottom surface, the light incident surface and the third quasi-plane, and the inclination directions of the second sub-surfaces relative to the third quasi-plane are opposite.
  10. 10. The light guide element of claim 9, wherein the light-facing surface further comprises a plurality of connector facets, The plurality of connection sub-surfaces are connected between the plurality of first sub-surfaces and the plurality of second sub-surfaces and are respectively positioned at two sides of the third quasi-plane.
  11. 11. The light guide element of claim 10, wherein the first plurality of sub-facets, the second plurality of sub-facets, and the connecting plurality of sub-facets are each curved.
  12. 12. The light guide element of claim 10, wherein the first plurality of sub-facets are respectively a plurality of planar surfaces, the second plurality of sub-facets are respectively a plurality of planar surfaces, and the connecting sub-facets are respectively a plurality of curved surfaces.
  13. 13. The light guide element of claim 10, wherein the first plurality of sub-facets are each a plurality of planes, the second plurality of sub-facets are each a plurality of planes, the connection sub-facets are each a plurality of planes, and the connection sub-facets are inclined in opposite directions with respect to the third quasi-plane.
  14. 14. The light guide element of claim 1, wherein the light-facing surface of the optical microstructure is at an angle of attack θ with respect to a plane to be extended of the bottom surface of the body, and 2 ° < θ <35 °.
  15. 15. The light guide element of claim 1, wherein the optical microstructure has a maximum depth H recessed into the bottom surface, and 2 μιη < H <30 μιη.
  16. 16. The light guide element according to claim 1, wherein 10 μm < W y <100 μm.
  17. 17. A backlight module is characterized in that the backlight module comprises a light guide element and a light source, wherein The light guide element comprises a main body and an optical microstructure, wherein The main body comprises a bottom surface, a light emitting surface and a light entering surface, wherein The light-emitting surface is arranged opposite to the bottom surface, and The light incident surface is connected between the light emergent surface and the bottom surface, and The optical microstructure is recessed in the bottom surface of the main body, wherein the optical microstructure comprises a light-receiving surface and a light-receiving surface, wherein The light incident surface faces the light incident surface, and The backlight surface is opposite to the light incident surface, and the light incident surface is positioned between the backlight surface and the light incident surface; The first quasi-plane is perpendicular to the light incident surface and parallel to the bottom surface, the light incident surface is provided with a first cross section line on the first quasi-plane, the first cross section line is provided with a first vertex close to the light incident surface and a plurality of first endpoints far away from the light incident surface and respectively positioned at two sides of the first vertex, a first quasi-arc line passes through the first vertex and the plurality of first endpoints, the first quasi-arc line is provided with a curvature radius R xy , and R xy is 15 mu m <60 mu m; The second quasi-plane is parallel to the light incident surface and perpendicular to the bottom surface, the light incident surface is provided with a second truncated line on the second quasi-plane, the second truncated line is provided with a second vertex close to the light emergent surface and a plurality of second endpoints far away from the light emergent surface and respectively positioned at two sides of the second vertex, a second quasi-arc line passes through the second vertex and the second endpoints, the second quasi-arc line is provided with a curvature radius R xz , and R xz is 30 μm; the radius of curvature R xz of the second quasi-arc is greater than the radius of curvature R xy of the first quasi-arc; The optical microstructure has a first width W x in a first direction parallel to the light incident surface and the bottom surface, a second width W y in a second direction perpendicular to the light incident surface and parallel to the bottom surface, and a first width W x greater than a second width W y , and The light source is arranged beside the light incident surface.

Description

Light guide element and backlight module Technical Field The present invention relates to an optical device and an optical module, and more particularly, to a light guide device and a backlight module. Background The backlight module comprises a light source, a light guide element, a reflecting sheet and an optical film group. Light emitted by the light source enters from the light incident surface of the light guide element and is transmitted in the light guide element. The light can be guided out of the light guide element through the special design of the surface of the light guide element. The light guided out of the light guide element can be converged and properly mixed through the prism sheet and the diffusion sheet of the optical film to form a surface light source. With the popularity of backlight modules, there is a trend to improve the performance of backlight modules. There are various ways to increase the brightness of the module, such as matching with high gain optical film or increasing the number of light emitting devices. The price is usually increased while the optical film with high gain is matched or the number of light emitting elements is increased. Is not accepted by the market due to cost pressure and high gain optical film or the way of increasing the number of light emitting elements. Therefore, the optical microstructure with high directivity is applied to the light guide element to improve the light emitting efficiency of the backlight module. However, due to the characteristics of the high-directivity optical microstructure, the light rays have higher directivity when passing through the light emitting surface of the light guide element. When the light scattering effect of the high directivity optical microstructure is poor, uneven brightness is likely to occur on the light exit surface on the side close to the light entrance surface when the pitch of the light emitting elements is large. The background section is only for the purpose of aiding in the understanding of the present invention and thus the disclosure in the background section may contain some material that does not form the prior art that is not already known to those of skill in the art. The matters disclosed in the "background" section are not representative of the matters or problems to be solved by one or more embodiments of the present invention, and are known or recognized by those skilled in the art prior to the application of the present invention. Disclosure of Invention The invention provides a light guide element which can improve the uniformity of light emission. The invention provides a backlight module with good light emitting uniformity. Other objects and advantages of the present invention will be further appreciated from the technical features disclosed in the present invention. To achieve one or a part or all of the above or other objects, a light guide element according to an embodiment of the invention includes a main body and an optical microstructure. The main body comprises a bottom surface, an opposite light-emitting surface arranged on the bottom surface and a light-entering surface connected between the light-emitting surface and the bottom surface. The optical microstructures are recessed into the bottom surface of the body. The optical microstructure comprises a light incident surface facing the light incident surface and a light back surface facing away from the light incident surface. The light-receiving surface is positioned between the backlight surface and the light-entering surface. The first quasi-plane is perpendicular to the light incident surface and parallel to the bottom surface. The light-receiving surface has a first truncated line on the first quasi-plane. The first truncated line is provided with a first vertex close to the light incident surface and a plurality of first endpoints far away from the light incident surface and respectively positioned at two sides of the first vertex. The first quasi-arc line passes through the first top point and a plurality of first end points. The first quasi-arc has a radius of curvature R xy, and 15 μm < R xy <60 μm. The second quasi-plane is parallel to the light incident surface and perpendicular to the bottom surface. The light-receiving surface has a second truncated line on the second quasi-plane. The second truncated line is provided with a second vertex close to the light-emitting surface and a plurality of second endpoints far away from the light-emitting surface and respectively positioned at two sides of the second vertex. The second quasi-arc line passes through the second top point and a plurality of second end points. The second quasi-arc has a radius of curvature R xz, and 30 μm < R xz <120 μm. The radius of curvature R xz of the second quasi-arc is greater than the radius of curvature R xy of the first quasi-arc. The optical microstructure has a first width W x in a first direction parallel to the light incident surface an