JP2002043629A - Led projector and lens body for use therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize an LED projector and a lens for use therein in which light beams radiated sideward from an LED, as well as light beams in the central part, can be focused and condensed entirely with high condensation efficiency in an optical device comprising an LED light source. SOLUTION: The LED projector comprises an LED light source device, and a lens body for focusing light from the light source of the LED light source device and projecting the focused light in a specified direction. The lens body comprises a central prism formed in the center of the lens body and focusing light from the light source within a specified angular range by refraction, and an outer ring prism standing on the circumference of the central prism to form a recess and leading in the light from the light source deviating from the specified angular range before focusing by total reflection. Light source of the LED light source device is disposed in the recess and the light from the light source is received entirely by the lens body before being projected in a specified direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED light emitting device which captures and focuses light from a light source such as an LED to the maximum and emits light in a predetermined direction, and a lens body thereof.

[0002]

2. Description of the Related Art LEDs (light emitting diodes)
C) consumes a small amount of power and generates a small amount of heat. Therefore, it has been receiving attention as a light source that can be applied to various uses as its brightness increases and the development of white LEDs progresses. There are various types of LEDs as a light source, and a chip L of a type directly mounted on a printed circuit board by an automatic mounting machine or a bonder.
ED and LED bare chips are excellent from the viewpoint of productivity and reliability. Now, since LEDs diffuse light and illuminate the surface dark, a condensing lens is indispensable for use in various devices and devices that need to project light over a predetermined distance.

FIG. 10 shows an LED using a conventional condenser lens.
FIG. 3 is a diagram illustrating a light condensing state. In the figure, 1 is LE
D and 2 are convex lenses that receive and refract the light of the LED 1 and focus and project the light in a predetermined direction. In order to focus light in a predetermined direction, the LED 1 is installed near the focal point of the convex lens 2. However, when the focal length is long, the lateral radiation light that cannot be captured by the lens increases. Reducing the focal length increases the lateral radiation that can be captured by the lens, but also increases the surface reflection loss at the lens. Part of the light beam (arrow) incident on the convex lens 1 is reflected by the lens surface as shown in the figure,
A so-called surface reflection loss occurs. The surface reflection loss rate is, for example, an acrylic lens (refractive index n = 1.485).
, The reflection loss ratio at an incident angle of 0 degree is about 3.8%.
And this value increases as the angle of incidence increases.

[0004] Under such circumstances, the light receiving range of the convex lens 2 out of the radiated light of the LED 1 usually has to be set to 60 to 70 degrees, and at present, the remaining light cannot be collected.

[0005]

According to the present invention, there is provided an LED light emitting device comprising an LED light source device and a lens body for converging light from the light source of the LED light source device and irradiating the light in a predetermined direction. The body is formed at the center of the lens body and is provided so as to form a concave portion so as to rise around the central prism portion and to form a recess around the central prism portion for refracting and condensing light within a predetermined angle range from the light source. An outer ring prism portion that guides light outside the predetermined angle range to the inside and totally reflects and converges the light, and the light source of the LED light source device is installed in the concave portion, so that the light from the light source is An object of the present invention is to solve the above-mentioned conventional problems by receiving all the light on a lens body and projecting the light in a predetermined direction.

In the above construction, the central prism portion is formed in a conical or pyramid shape, and the outer ring prism portion has an inner wall portion suspended around the central prism portion and a slope portion inclined downward and outward from the top of the inner wall portion. The central prism section also converges the surface reflection light on the outer ring prism section by refraction, and the outer ring prism section also guides the surface reflection light on the center prism section to the inside so as to be totally reflected and converge. There is.

In the above construction, the central prism portion is constituted by a curved projection, and the outer ring prism portion is a concave inner wall portion erected around the central prism portion and is inclined outward from the top of the concave inner wall portion. There is a case where the light from the light source is projected as a parallel light through a lens body by being formed by a descending convex curved surface portion.

Further, an LED light emitting device may be formed by arranging a plurality of LED light source devices and lens bodies in parallel.

The present invention is further provided with a central prism portion formed at the center for focusing light within a predetermined angle range from the light source by refraction, and a concave portion rising around the central prism portion. An outer ring prism portion that guides light out of the predetermined angle range from the light source to the inside and totally reflects and converges the light. The lens body receives all light from the light source located in the concave portion and emits the light in a predetermined direction. An object of the present invention is to solve the above-mentioned conventional problems by providing a lens body which is configured as described above.

In the above-mentioned lens body, the central prism portion is formed in a conical or pyramid shape, and the outer ring prism portion is inclined downward and outward from an inner wall portion suspended around the central prism portion and a top of the inner wall portion. The central prism portion is formed by the refraction of the surface reflection light on the outer ring prism portion, and the outer ring prism portion also guides the surface reflection light on the center prism portion to the inside to be totally reflected and focused. There are things to do.

Further, in the lens body, the central prism portion is constituted by a curved surface projection, and the outer ring prism portion is a concave inner wall portion provided upright around the central prism portion and extends outward from the top of the concave inner wall portion. There is a case where the light from the light source is projected as a parallel light through a lens body by being formed by a convex curved surface portion which is inclined downward.

[0012]

Embodiments of the present invention will be described below. FIG. 1 is a cross-sectional view of the LED floodlight device according to the first embodiment of the present invention. In the figure, reference numeral 1 denotes an LED light source device, which includes an LED, a mounting base on which the LED is mounted, and a lead wire. The LED light source device 1 is fixed to the lens body 2 via a back cover that fits into a cylindrical skirt portion that stands upright around the lens body 2.

The lens body 2 made of acrylic resin is
A central prism portion 3 formed in a central portion and converging light within a predetermined angle range from the LED as a light source by refraction;
An outer ring prism portion 4 is provided so as to rise around the central prism portion 3 to form a concave portion 5 and guides light outside the predetermined angle range from the LED as a light source into the interior and totally reflects the light to converge. Have been. And the LED
The light source LED of the light source device is arranged in the recess 5, more specifically, at a position where light is emitted at the focal point F of the lens body 2.

The central prism portion 3 is formed in a conical shape in this embodiment, but may be formed in a triangular pyramid or a polygonal pyramid. In this embodiment, the central prism portion 3
Has an isosceles triangular shape, the apex angle is set to about 100 degrees, and the focal point F is set so that the incident angle of light at the center of the inclined surface of the central prism portion 3 having a conical shape is about 60 degrees. Is set. Further, the outer ring prism portion 4 is formed by an inner wall portion 4a which stands upright around the central prism portion 3 and a slope portion 4b which is inclined downward and outward from the top of the inner wall portion 4a. The intersection angle between the inner wall portion 4a and the slope portion 4b is slightly larger than the critical angle for total reflection 42.33 degrees45.
It is formed every time. It should be noted that the critical angle for total reflection is derived by a known calculation in the case of air and acrylic resin.

FIG. 2 is a diagram showing a state of light focusing by the lens body 2 in the LED light emitting device shown in FIG. LE
Since D is located at the focal point in the concave portion 5 formed by the inner wall portion 4a, all of the emitted light (arrows) passes through the lens body 2 and is focused, and the front edge of the lens 2 ( Light is emitted from below). That is, LED as a light source
The light within a predetermined angle range is guided into the central prism portion 3, is focused by refraction, and is projected from the front edge (the lower side in the figure) of the lens body 2. Further, the light outside the predetermined angle range from the LED reaches the inner wall portion 4a and is guided to the inside of the outer ring prism portion 4 and then is totally reflected by the inclined surface portion 4b and is reflected by the lens body 2.
Is focused and projected from the front edge (below in the figure).

On the other hand, a part of the light reaching the lens body 2 from the LED is divided into a central prism portion 3 and an outer ring prism portion 4.
In any one of the incident surfaces, so-called surface reflection occurs, but the light reflected on the surface is eventually received by the lens body 2 and converged and projected from the front edge (the lower side in the figure) of the lens body 2. . This will be described with reference to FIG. Part 6a of the light ray 6 emitted from the focal point F of the lens body 2 and incident on the outer ring prism part 4 is guided into the outer ring prism part 4, is totally reflected on the slope part 4b, and is the front edge of the lens body 2 (downward in the figure). Is emitted from When the light ray 6 is incident on the inner wall portion 4a, it generates surface reflected light 6b. The surface reflected light 6b enters the central prism portion 3 as shown in FIG.
Light is emitted from the front edge (the lower side in the figure) of the lens body 2.

Then, a part 7a of the light ray 7 emitted from the focal point F of the lens body 2 and incident on the central prism section 3 is guided into the central prism section 4 and refracted, thereby leading the front edge of the lens body 2 (downward in the figure). Is emitted from The light ray 7 generates surface reflected light 7b when entering the central prism portion 3. The surface reflected light 7b enters the outer ring prism portion 4 as shown in FIG. The light is emitted from the front edge (lower side in the figure) of No. 2.

FIG. 4 is a diagram showing an L according to a second embodiment of the present invention.
It is sectional drawing which shows an ED light projection apparatus. In this embodiment, the central prism portion 3 is formed of a curved surface projection, and the outer ring prism portion 4 is a concave inner wall portion 41 erected around the central prism portion 3 and extends outward from the top of the concave inner wall portion 41. It is formed by a convex curved surface portion 42 that is inclined downward. In this way, all light beams (arrows) from the light source at the focal point F are projected as almost perfect parallel light through the lens body 2, and are widely used as spatial light transmission data communication and spotlights. Applications can be expected.

Although the curved surface of the curved projection constituting the central prism portion 3 is aspherical, the concave inner wall portion 4 has a curved surface.
Reference numeral 1 denotes a part of a spherical surface having a predetermined radius around the focal point F. Further, the convex curved surface portion 42 is formed as an aspheric surface. That is, the central prism portion 3
Is an aspheric convex lens surface whose focal point is the light source position F, and the convex curved surface portion 42 is a parabolic surface or an elliptical surface whose focal point is the light source position F. Of the light from the light source position F, light within a predetermined range enters the central prism portion 3 and is refracted and emitted as parallel light from the surface of the lens body 2 (below in the figure). On the other hand, the remaining light reaches the convex curved surface portion 42 via the concave inner wall portion 41 and is reflected. The incident angle of the convex curved surface portion 42 of light is at least 45 degrees (the incident angle of light traveling horizontally from the light source) or more, and the critical angle for total reflection 42.3.
Since the angle is larger than 3 degrees, the light is totally reflected by the convex curved surface portion 42 and then emitted out of the lens in parallel to the optical axis.

FIG. 5 is a sectional view showing an embodiment of an LED light emitting device in which a plurality of LED light source devices and lens bodies 2 are arranged in parallel. In this embodiment, the lens body 2 shown in FIG. 2 is used. The lens bodies 2 are integrally connected to each other to form a collective lens 21. Since the lens body 2 is circular, a gap area is generated between the lens bodies 2 and it is inevitable that light unevenness occurs as a whole. However, the surface of the collective lens 21 is processed into a bare surface or a milky white film is attached. Then, the light may be diffused.

FIG. 6 is a plan view showing another embodiment of a collective lens in which a plurality of lens bodies 2 are juxtaposed in the same manner as described above. The collective lens 31 is formed by integrally connecting a plurality of lens bodies 2. In this embodiment, the central prism portion 3 of the lens body 2 is formed in a quadrangular pyramid shape, and the lower four sides of the quadrangular pyramid are formed. An outer ring prism section 4 is provided upright. FIG. 7 is a sectional view taken along line AA in FIG. In this embodiment, the lens bodies 2 are in close contact with each other without any gap, and unlike the above-described embodiments, no uneven light is generated.

FIG. 8 is a plan view showing still another embodiment of a collective lens in which a plurality of lens bodies 2 are arranged side by side in the same manner as described above. The collective lens 52 is formed by integrally connecting a plurality of lens bodies 2. In this embodiment, the central prism portion 3 of the lens body 2 is formed in a hexagonal pyramid shape. An outer ring prism section 4 is provided upright. FIG. 9 is a sectional view taken along line AA in FIG.

In the LED light emitting device according to the present invention, the color selection of the LED can be variously set depending on the application. For general applications such as lighting devices, white LEDs
Alternatively, a fluorescent plate that emits white fluorescent light by ultraviolet light or blue light may be provided on the lens surface using a blue LED. In addition, each LED using three primary color LEDs
By controlling the brightness of the display device, its application range is versatile as a lighting device or a display device.

[0024]

According to the present invention, as described above, an LED having an excellent photoelectric conversion rate is used as a light source, and the entire range of light flux from this LED can be converged and emitted in a predetermined direction, so that the energy efficiency is extremely high. A light projecting device can be realized, and its application range including a novel lighting device or display device is not limited.

[Brief description of the drawings]

FIG. 1 is a sectional view of an LED floodlight device according to a first embodiment.

FIG. 2 is a sectional view of a lens body of the LED light emitting device shown in FIG.

FIG. 3 is an operation explanatory view of the lens body shown in FIG. 2;

FIG. 4 is a sectional view of an LED floodlight device according to a second embodiment.

FIG. 5 is a sectional view of an LED floodlight device according to a third embodiment.

FIG. 6 is a plan view of a collective lens according to an LED floodlight device according to a fourth embodiment.

FIG. 7 is a sectional view taken along line AA in FIG.

FIG. 8 is a plan view of a collective lens according to an LED floodlight device according to a fifth embodiment.

9 is a sectional view taken along line AA in FIG.

FIG. 10 is a cross-sectional view showing a conventional technique.

[Explanation of symbols]

 1. . . . . . LED light source device 2. . . . . . Lens body 3. . . . . . Central prism part 4. . . . . . Outer ring prism section 4a. . . . . Inner wall 4b. . . . . Slope 5. . . . . . Recess 41. . . . . Concave inner wall portion 42. . . . . Convex curved surface

Claims (7)

[Claims] 1. An LED light source device, and a lens body for converging light from the light source of the LED light source device and irradiating the light in a predetermined direction, the lens body being formed at the center of the lens body and having a predetermined angle from the light source. A central prism portion that converges light within the range by refraction, and is provided so as to rise around the central prism portion to form a concave portion, guides light out of the predetermined angle range from the light source to the inside, and totally reflects the light. With a focusing outer ring prism,
An LED light emitting device, wherein a light source of the LED light source device is installed in the recess, and all light from the light source is received by a lens body and emitted in a predetermined direction. 2. The method according to claim 1, wherein the central prism portion is formed in a conical or pyramid shape, and the outer ring prism portion is inclined downward and outward from an inner wall portion suspended around the central prism portion and a top of the inner wall portion. The central prism portion is formed by the refraction of the surface reflection light on the outer ring prism portion, and the outer ring prism portion also guides the surface reflection light on the center prism portion to the inside to be totally reflected and focused. An LED floodlight device, characterized in that: 3. The central prism portion according to claim 1, wherein the central prism portion is constituted by a curved surface projection, and the outer ring prism portion is a concave inner wall portion erected around the central prism portion and extends outward from the top of the concave inner wall portion. Formed by a convex curved surface part that slopes down,
An LED light emitting device, wherein light from a light source is emitted as parallel light through a lens body. 4. The LED floodlight device according to claim 1, wherein a plurality of LED light source devices and lens bodies are arranged in parallel. 5. A central prism portion formed at the center and refracting and converging light within a predetermined angle range from the light source, and said central prism portion is provided so as to rise around the central prism portion to form a concave portion. An outer-ring prism portion that guides light outside the predetermined angle range to the inside and totally reflects and converges the light, and receives all light from a light source located in the concave portion to the lens body and projects the light in a predetermined direction. A lens body characterized in that: 6. The center prism portion according to claim 5, wherein the central prism portion is formed in a conical or pyramid shape, and the outer ring prism portion is inclined downward and outward from an inner wall portion suspended around the central prism portion and a top of the inner wall portion. The central prism portion is formed by the refraction of the surface reflection light on the outer ring prism portion, and the outer ring prism portion also guides the surface reflection light on the center prism portion to the inside to be totally reflected and focused. A lens body characterized in that: 7. The central prism portion according to claim 5, wherein the central prism portion is constituted by a curved surface projection, and the outer ring prism portion extends outward from a concave inner wall portion erected around the central prism portion and a top of the concave inner wall portion. It is formed by a convex curved surface part that slopes down,
A lens body characterized in that light from a light source is projected as parallel light through a lens body.