Lens member and light-emitting device using same

Abstract

The invention provides a lens member and a light-emitting device having high light-collecting ability, and which enable further reduction in thickness. A lens member having a light incidence surface (10a), a light emission surface (10b) on the opposite side from the light incidence surface (10a), a Fresnel lens (14) disposed on the central axis (AX) through the center of the light incidence surface (10a), and a diffraction grating structure (15) disposed outside the Fresnel lens (14) and centered around the central axis (AX), the Fresnel lens (14) being provided with a first Fresnel lens (14a) having a plurality of annular prisms which are divided from a convex lens and disposed so as to be centered around the central axis (AX) of the light incidence surface (10a), and a second Fresnel lens (14b); having a plurality of annular prisms which are divided from a TIR lens and disposed outside the first Fresnel lens (14a) so as to be centered around the central axis (AX) of the light incidence surface (10a).

Description

technical field [0001] The present invention relates to a lens component and a light emitting device in which the lens component and a light source are arranged opposite to each other. Background technique [0002] In recent years, light-emitting devices using light-emitting diodes (LEDs) as light sources have increased among light-emitting devices such as lighting, projectors, strobes, and headlights and tail lights of automobiles. Such a light emitting device, particularly a device used as a light source of a narrow directivity LED, uses a lens that condenses or collimates light emitted from the light emitting surface of the LED. As such a lens, a convex refracting lens is generally used, but since the convex portion has a thickness, it has been proposed to use a Fresnel lens in order to reduce the thickness. [0003] Conventionally, a lens of a lamp has been proposed in which a grating-shaped refraction system prism portion is provided in the center near the optical axis...

AI Technical Summary

Problems solved by technology

[0004] However, in the above-mentioned Fresnel lens, when the incident surface of the prism and the reflection surface of the prism constitute the tip of the prism at an acute angle, when the mold is filled with resin, the tip may be thin and the resin may not enter the tip.

In this case, there is the following problem: the tip of the prism has roundness, the incident and reflection of light with high precision cannot be performed at the tip of the prism, and the performance of the front illuminance of the light exit surface of the Fresnel lens and the like deteriorates. reason

Therefore, even if the TIR lens 1 is directly transformed into a Fresnel lens by the conventional method, the emitted light is the same as that of the TIR lens 1, and an annular unnecessary light (reflection spot) centered on the optical axis is generated, leaving unsightly problem

Furthermore, in the lens described in Patent Document 3, since both the light incident surface and the light emitting surface of the reflective lens part are aspheric, there is a problem that it is difficult to process and the cost is high when turning it into a Fresnel lens.