JPH036602B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a light emitting diode (hereinafter abbreviated as LED).
This invention relates to a lighting device that uses a light-emitting element such as the above as a light source, and is particularly designed to effectively utilize light emitted diagonally forward from the light-emitting element to improve the lighting effect.

[Conventional technology]

In recent years, with the development of semiconductor technology, brightness has increased.
Since LEDs have been developed and are now available at low prices, their use in place of light bulbs as a light source for vehicle lighting, especially brake lights and taillights, is being considered. The one shown in Figure 4 is known. That is, this lighting device 1 includes a printed circuit board 3 on which a large number of LEDs 2 are arranged in a matrix at predetermined intervals, and a plurality of LEDs 2 arranged on the surface of this printed circuit board 3.
A large number of condensing lenses 5 are formed on the surface of the lens 4 to correspond to each of the LEDs 2, respectively. The condensing lens 5
It is for condensing the light 6 that is emitted from the LED 2 and passing through the inner lens 4 and guiding it forward. It is made up of approximately hemispherical spherical lenses (fisheye lenses), and they are formed closely together without any gaps as shown in Figure 5. As a result, the bottom portion 5a forms a rectangle.
Note that 7 is a conductive pattern and 8 is wire bonding.

[Problem to be solved by the invention]

However, in such a conventional lighting device 1,
The light emitted from LED2 and directed diagonally forward is the corresponding LED.
The light could not be effectively incident on the condensing lens 5 corresponding to No. 2, and there was a problem in terms of effective use of the light. That is, if the solid angle of the light 6 emitted from the LED 2 that passes through the condensing lens 5 corresponding to the LED 2 is θ, then the light 6' emitted at an angle larger than this solid angle θ will pass through the adjacent condensing lens. Since the light is emitted in a direction that does not enter the interior of the light source 5, it does not participate as illumination light, in other words, it results in a loss of light and reduces the illumination effect. Therefore, it is desirable to set the solid angle θ large, but this solid angle θ is determined by the distance between the LED 2 and the lens 4, the size of the condensing lens 5, the refractive index of the lens itself, etc. However, it was not possible to increase the light utilization efficiency unless these dimensions and refractive index were changed.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and its purpose is to condense light without changing the size of the condenser lens or the refractive index of the lens itself. An object of the present invention is to provide an illumination device that can increase the solid angle of light passing through a lens and improve the efficiency of light utilization.

[Means to solve the problem]

In order to achieve the above object, the present invention arranges an inner lens between an outer lens having a large number of diffusing lenses formed on the inner surface and a substrate having a large number of light emitting elements arranged at predetermined intervals on the surface. A large number of condensing lenses that are in close contact with each other are formed on the surface of this inner lens corresponding to each of the light emitting elements, and a large number of auxiliary lenses each having a convex curved surface at least at a peripheral edge are formed on the back surface of each of the condensing lenses. It was formed in response to the

[Effect]

In the present invention, oblique light that comes out of the light emitting element and enters the convex curved surface of the auxiliary lens is largely refracted by the convex curved surface despite having a large solid angle. The periphery of the optical lens is irradiated and transmitted.

〔Example〕

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 is a sectional view of a main part of an embodiment of a lighting device according to the present invention. In the figure, in this embodiment, a lamp body 12 is composed of an outer lens 10 and a back cover 11, and an inner lens 13 is provided inside the lamp body 12.
A board 14 is provided, and a large number of LEDs are arranged in a matrix at predetermined intervals on the front surface of the board 14, and a resistor (not shown) for lighting the LEDs is arranged on the back surface. It is.

The outer lens 10 is attached to the back cover 11 so as to cover the front opening of the back cover 11, and a diffusion lens 15 consisting of a large number of small convex lenses is densely formed on the inner surface.

The inner lens 13 is disposed behind the outer lens 10, and a large number of condensing lenses 5 are formed protruding from the surface of the inner lens 13, corresponding to each of the LEDs 2. Similar to the conventional device shown in FIG. 4, the condensing lenses 5 are composed of substantially hemispherical spherical lenses (fisheye lenses), and adjacent lenses are provided in close contact with each other.

On the other hand, a large number of auxiliary lenses 16 are formed protruding from the back surface of the inner lens 13, corresponding to each of the condensing lenses 5. This auxiliary lens 16 has approximately the same size as the bottom portion 5a of the condensing lens 5, has the same thickness t over almost the entire surface, and has a peripheral portion chamfered with an appropriate curvature to form a convex curved surface portion 17, The boundary with the adjacent auxiliary lens is clearly defined.

The substrate 14 is disposed behind the inner lens 13. The LED2 is for each column (or row)
They are connected in series and connected in parallel to a power source (not shown).

Thus, according to the lighting device having such a configuration, the distance between the LED 2 and the inner lens 13,
The solid angle of light can be set large without changing the size of the condenser lens 5, the refractive index of the inner lens 13, etc., and the loss of light can be reduced. That is, as shown in Figure 2, the LED
2 and is refracted by the convex curved surface portion 17 of the auxiliary lens 16, and the boundary portion 2 between the adjacent condenser lens 5'.
If the solid angle of the light 20 emitted from the inner lens is θ ₁ , this solid angle θ ₁ is the same as the light 6' in the conventional device shown in FIG.
Compared to the solid angle θ, the incident point P ₁ moves to the outside of P ₀ , so it is large (θ ₁ > θ), and therefore,
Light utilization efficiency increases, allowing for brighter illumination. In this case, it will be easily understood that the solid angle θ ₁ can be changed depending on the curvature of the convex curved surface portion 17.

Further, in this embodiment, the outer lens 10
Since the light passing through the lens 10 is diffused by the diffusion lens 15 of the outer lens 10, the part corresponding to the LED 2 is not locally brightened, and the outer lens 10
The entire surface can be illuminated with almost uniform brightness.

Figures 3a and 3b show other embodiments of the auxiliary lens, in which figure a shows the auxiliary lens 16 made up of a convex lens, and figure b shows a concave lens 25 and a convex lens provided around the concave lens 25. The curved surface 17 constitutes an auxiliary lens 16. It is obvious that the solid angle of light can be increased in the auxiliary lens 16 having such a configuration as well, as in the above embodiment. However, the light distribution varies depending on the shape of the auxiliary lens 16. That is, in the embodiment structure shown in FIG. 1 and FIG. Prevent the center from becoming brighter than the periphery.

Incidentally, in the above embodiments, the case where the condensing lenses 5 are provided closely together has been described, but the present invention is not limited to this, and it goes without saying that the condensing lenses 5 may be provided separately.

〔Effect of the invention〕

As explained above, in the lighting device according to the present invention, a large number of condensing lenses that are in close contact with each other are provided on the surface of the inner lens corresponding to each light emitting element, and a large number of auxiliary lenses whose periphery has a convex curved surface are provided on the back surface of the inner lens. Since it is provided corresponding to each condensing lens, the solid angle of light incident on the condensing lens section can be increased by the convex curved surface compared to a conventional device that does not include an auxiliary lens. Therefore, there is less light loss, allowing brighter illumination and improving lighting effects. Furthermore, the formation of the auxiliary lens is also simple.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of essential parts showing one embodiment of the present invention;
Figure 2 is a diagram for explaining the effects of the present invention, Figure 3 is a diagram for explaining the effects of the present invention.
Figures a and b are views showing other embodiments of the auxiliary lens, Figure 4 is a sectional view of essential parts of an example of a conventional device, and Figure 5 is a perspective view of the lens. 2...LED, 3...Printed circuit board, 4...lens, 5...condensing lens, 10...outer lens, 11...back cover, 12...lamp body, 13
... Inner lens, 14 ... Substrate, 15 ... Diffusion lens, 16 ... Auxiliary lens, 17 ... Convex curved surface portion.

Claims (1)

[Claims] 1. An outer lens having a large number of diffusion lenses formed on its inner surface and forming the front surface of the lamp body, a substrate having a large number of light emitting elements arranged on its surface at predetermined intervals and located behind the outer lens, and this substrate. an inner lens disposed between the outer lens, a number of condensing lenses that are in close contact with each other are formed on the surface of the inner lens corresponding to the light emitting elements, and at least a peripheral edge portion is convex on the back surface. An illumination device characterized in that a large number of auxiliary lenses each having a curved surface are formed corresponding to each of the condensing lenses.