JP2007266180A - Lens for light-emitting element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting element lens which efficiently and uniformly radiates a light forwards from the emitting element without complicating the lens shape. <P>SOLUTION: The light emitting element lens 1 has a forwards radially expanded lens body and a convex lens part 6 projecting in front of the lens body from its front center with its outside forming a flat surface 4, and once total-reflects a light of a light emitting element disposed on the lens body bottom from the side wall 3 of the lens body to it radiate forwards. The lens 1 comprises an approximately circular columnar hollow 7 in a lens lower side wall where the light emitting element 2 locates. Light from the emitting element 2 toward the hollow's side wall 7b makes incidence at a total reflection angle or less to pass through the lens and then at the total reflection angle or greater on the lens side wall to total-reflect, thereby radiating the light in front of the lens body, while a light from the emitting element toward the topside 7a of the hollow makes incidence at a total reflection angle or less to pass through the lens and is condensed by the convex lens part and radiated forwards. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a condensing lens that covers and arranges an upper part of a light emitting element such as an LED (light emitting diode) chip used in a display device or the like, and particularly focuses light from a light emitting element with a small diameter. The present invention relates to a lens for a light emitting element that can efficiently and suitably irradiate with a wide light emitting area.

Originally, the light emitting area of the light emitting element such as LED is pinpoint, and if it is left as it is, it becomes non-directional illumination and the light diffuses, and a light emitting surface of a certain area cannot be formed, and from a long distance. Therefore, a condensing lens for converging light is usually provided covering the front of the light emitting element. As this condensing lens, a light emitting element mounting portion is formed at the bottom, and the light of the central portion irradiated from the light emitting element is condensed by a convex portion formed at the center of the front surface of the lens, and the light outside thereof is There is one that totally reflects on the wall surface that draws a parabolic curve from the bottom and radiates forward.
Japanese Utility Model Publication No. 6-28725

  However, the above-described conventional lens for light emitting element has a structure in which a deep ring-shaped groove is formed so that a convex portion is formed at the center of the lens front surface. It is very difficult to form a lens with a large shape and a large curvature. Especially in a lens body with a high height, the ring-shaped groove becomes too deep, and depending on the size and material of the lens, the light from the light emitting element is not necessarily used. It was not always possible to irradiate the front efficiently without unevenness.

  Accordingly, in order to solve the above-described problems, the present invention provides a lens for a light-emitting element that can efficiently irradiate light from the light-emitting element without unevenness without complicating the shape of the lens. Objective.

  In order to achieve the above object, the lens for a light-emitting element of the present invention has a convex lens portion projecting toward the front of the lens body at the center of the front surface of the lens body whose diameter increases toward the front, and its outer periphery. In a lens for a light emitting element that emits light emitted from a light emitting element disposed on the bottom of the lens body and totally reflecting the light from the peripheral wall of the lens body to the front of the lens body, A substantially cylindrical hollow portion is provided in the peripheral portion of the light emitting element, and light traveling from the light emitting element toward the side peripheral surface of the hollow portion is incident at a total reflection angle or less corresponding to the refractive index of the lens body to enter the lens body. The transmitted light is incident on the peripheral wall of the lens body at a total reflection angle or more, is totally reflected, and is emitted forward from the flat portion of the front surface of the lens body, and is directed from the light emitting element to the upper surface of the hollow portion. When light is below the total reflection angle Characterized in that it is radiated forward from the convex lens portion of the lens directly anterior surface passes through the lens body shines.

  In addition, the upper surface of the hollow portion at the lower part of the lens body is formed in a convex shape downward, and a convex lens is formed as a whole together with the convex lens portion at the upper part.

  In addition, the light emitting element is molded by a synthetic resin material together with the wiring of the bonding wire.

  According to the lens for a light emitting element of the present invention, a convex lens part projecting toward the front of the lens body is projected at the front center part of the lens body that expands the width diameter toward the front, and its outer periphery is a flat part, In addition, in a lens for a light-emitting element that emits light emitted from a light-emitting element disposed at the bottom of the lens body to the front of the lens body after being totally reflected by the peripheral wall of the lens body, Is provided with a substantially cylindrical hollow portion, and light traveling from the light emitting element toward the side peripheral surface of the hollow portion is incident at a total reflection angle or less corresponding to the refractive index of the lens body and is transmitted through the lens body. The light is incident on the peripheral wall of the lens body at the total reflection angle or more and is totally reflected and radiated forward from the plane portion of the front surface of the lens body, and the light from the light emitting element toward the upper surface of the hollow portion is totally reflected. Incident below the angle and inside the lens Then, the light from the light emitting element is directly radiated forward from the convex lens portion on the front surface of the lens body, so that the light from the light emitting element is divided into light passing through the upper surface and light passing through the side peripheral surface in the hollow portion. The light passing therethrough is totally reflected by the peripheral wall of the lens body in accordance with the refractive index of the lens body and is preferably radiated forward from the plane part, and the light passing through the upper surface of the hollow part is preferably converged by the convex lens part. Such a lens for a light emitting element can be obtained without making it into a complicated shape.

  In addition, the upper surface of the hollow portion at the bottom of the lens body is formed into a convex spherical surface downward and the convex lens portion as a whole together with the upper convex lens portion forms a convex lens. By making the convex shape of the lens, the curvature of the convex lens portion protruding toward the front of the lens body can be reduced and the shape can be made reasonable, so that the light passing through the upper surface of the hollow portion converges to some extent in the convex shape. Then, the light is further condensed by the convex lens part and can be irradiated as a suitable convergent light in front of the lens body, and a suitable lens for a light emitting element can be obtained without increasing the curvature of the convex lens part.

  Moreover, the light emitting element is molded with a synthetic resin material together with the wiring of the bonding wire, so that the light emitting element and the wiring of the bonding wire to the light emitting element are reliably protected.

  1 to 2 show a light-emitting element lens 1 of the present invention. The light-emitting element lens 1 made of a transparent synthetic resin material such as acrylic having a maximum outer diameter of about 21 mm and a height of about 11.5 mm By forming a light-emitting element portion 2 formed by molding a light-emitting element such as an LED with a synthetic resin at the bottom thereof, which is formed into a substantially inverted truncated cone shape that gradually expands the width diameter. The light from the light emitting element is condensed and irradiated to the front of the lens as a bundle of a certain amount of light. The peripheral wall 3 of the light-emitting element lens 1 is formed in a unique curved surface slightly bulging outward from the lower end of the lens to the lens front surface 4 (the cross section is not limited to a continuous curved surface, and is formed by a plurality of inclined surfaces. Alternatively, the outer peripheral portion of the lens front surface 4 is a flat surface portion 5 and a convex lens portion 6 (about R6) having a convex front is formed at the center thereof so as to protrude forward from a position one step lower than the lens front surface 4. ing.

  A substantially cylindrical hollow portion 7 having a height that is too high to dispose the light emitting element portion 2 is provided at the lower portion of the light emitting element lens 1 and is approximately 1/3 of the lens height from the lower end of the lens. It is formed to be recessed in the depth (in the above-described conventional lens for a light emitting element, there is only a small-diameter hemispherical hollow portion in which the light emitting element is disposed at the lower end of the lens). The upper surface 7a of the hollow portion 7 is formed of a spherical surface (about R10) that protrudes downward from the lens, and the side peripheral surface 7b of the hollow portion 7 gradually decreases the hole diameter from the lower end of the lens toward the front of the lens. Thus, the hollow portion 7 is formed in a substantially cylindrical shape. The hole diameter, height, and taper of the hollow portion 7 are set according to the dimensions of the light emitting element portion 2 disposed therein, the refractive index according to the lens material, the outer dimensions of the lens, and the like.

  The light emitting element portion 2 is molded with a transparent synthetic resin material such as silicon in order to exhibit a certain degree of light collecting action while protecting the light emitting element 8 itself such as an LED and the bonding wire to the light emitting element 8. The covering body 9 is covered with a convex surface. Conventionally, the silicon varnish was applied around the light emitting element and the bonding wire with a brush. However, in this case, the radial light emission from the light emitting element becomes non-uniform, and as a result, suitable parallel light cannot be obtained. It was what was supposed to be.

  According to the light-emitting element lens 1 having such a configuration, as shown in FIG. 2, first, of the light irradiated from the light-emitting element part 2 converged to some extent by the covering body 9, the light is applied to the upper surface 7 a of the hollow part 7. The light that travels enters the convex curved surface of the upper surface 7a (is less than or equal to the total reflection angle corresponding to the refractive index of the lens), converges, travels straight through the lens, and is converged by the convex lens portion 6 on the front surface 4 of the lens. Refracted and irradiated in front of the lens. In the present embodiment, the curvature of the convex lens portion 6 is set according to the refractive index of the acrylic lens so that the light passing through the convex lens portion 6 is close to parallel light. And the light which goes to the side peripheral surface 7b of the said hollow part 7 from the light emitting element part 2 injects with respect to the side peripheral surface 7b below the total reflection angle according to the refractive index of a lens, and is refracted | reflected with respect to the surrounding wall 3. It is totally reflected by being incident at the total reflection angle or more, and is irradiated to the front of the lens through the flat portion 5 of the lens front surface 4.

It is a perspective view which shows the lens for light emitting elements of this invention. It is explanatory drawing which shows the optical path in the lens for light emitting elements of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emitting element lens 2 Light emitting element part 3 Perimeter wall 4 Lens front surface 5 Plane part 6 Convex lens part 7 Hollow part 7a Upper surface 7b Side peripheral surface 8 Light emitting element 9 Covering body

Claims (3)

  From the light emitting element disposed at the bottom of the lens body, a convex lens part projecting toward the front of the lens body is provided at the center of the front surface of the lens body whose diameter increases toward the front, and its outer periphery is a flat part. In the lens for a light emitting element that totally reflects the light emitted by the peripheral wall of the lens body and radiates the light forward, a substantially cylindrical hollow portion is provided in the periphery of the light emitting element below the lens body where the light emitting element is located, Light traveling from the light-emitting element toward the side peripheral surface of the hollow portion is incident at a total reflection angle or less corresponding to the refractive index of the lens body, passes through the lens body, and the light is totally reflected on the peripheral wall of the lens body. Incident above the corner and totally reflected and radiated forward from the plane portion of the front surface of the lens body, and light directed from the light emitting element toward the upper surface of the hollow portion is incident below the total reflection angle and transmitted through the lens body. Convex lens directly in front of the lens body Lens for a light emitting element, wherein the radiated forward from.   2. The lens for a light emitting element according to claim 1, wherein the upper surface of the hollow part at the lower part of the lens body is formed as a spherical surface convex downward, and constitutes a convex lens as a whole together with the convex lens part at the upper part.   The light-emitting element lens according to claim 1, wherein the light-emitting element is molded by a synthetic resin material together with the bonding wire.

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