JPH0138808Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention is applicable to in-vehicle signal lighting devices used in vehicles and other transportation equipment, lighting devices for signal lights installed on roads, etc., and other various display devices. The present invention relates to a lighting device using a light emitting diode as a light source having a relatively large light emitting surface, such as a light source used in a light emitting device.

(Prior Art) A lighting device using a conventional light emitting diode as a light source has a plurality of light emitting diodes 1 arranged in a plane so as to cover approximately the area necessary for display, as shown in FIG. 3 as a conventional example. A front lens 2, which has been optically processed such as a suitable prism, is disposed close to the lens.

(Problem to be Solved by the Invention) However, in the above-mentioned conventional technology, the light emitting diode 1 and the front lens 2 are placed as close as possible to prevent shading on the display surface when observing the display surface from an oblique direction. This combined with the fact that the light emitted from the light emitting diode is a point light source with a certain divergence angle means that no matter how precise the optical processing is applied to the front lens 2, it cannot be perfect. Surface emission cannot be obtained, and as a result, even when the light emitted from each of the light emitting diodes 1 passes through the front lens 2, there are still noticeable light spots, which gives the viewer a sense of low quality and unnecessarily dazzling light. In addition, if one of the light emitting diodes 1 is broken, a black spot appears at that location, making the displayed content unclear.

(Means for Solving the Problems) The present invention is a specific means for solving the above-mentioned conventional problems, in which the focal point of the paraboloid of revolution is A plurality of light emitting diodes emitting at least a single color are arranged on the spherical surface at the center and at a position where the lead-side extension of the main optical axis passes through the focal point, including the front lens side. The above-mentioned problems are solved by providing an illumination device characterized in that a light emitting surface without light spots can be obtained.

(Example) Next, the present invention will be described in detail based on an example shown in the drawings.

What is indicated by the reference numeral 1 in FIG. 1 is a plurality of light emitting diodes, which are combined with a front lens 2 that has been optically processed such as a prism and a reflecting mirror 3 that is a paraboloid of revolution to form a lighting device. There is.

FIG. 2 shows an enlarged view of the attached state of the light emitting diode 1 serving as a light source in order to explain the gist of the present invention in more detail.

In the figure, the light emitting diode 1 is disposed on a surface equidistant from the focal point 4 of the paraboloid of revolution of the reflecting mirror 3, a part of which is shown, on a spherical surface 5. The direction is such that a line extending toward the lead side of the main optical axis 6 passes through the focal point 4 of the reflecting mirror 3. More specifically, the color and number of the light emitting diodes arranged on the spherical surface 5 are arbitrary. It is preferable to arrange the number of light emitting diodes without uneven light distribution depending on the light emitting angle of the type of light emitting diode used.

(Function) By arranging the light emitting diodes 1 by the method described above, all of the plurality of light emitting diodes 1 have their main optical axes 6 passing through the focal point 4, and therefore, the plurality of light emitting diodes 1 pass through the focal point 4. The light emitted from the diode 1 is completely equivalent to that emitted from a point light source virtually present at the focal point 4.

As a result, the light rays 7 shown in FIG. 1 are reflected by the reflecting mirror 3 so as to have an even illuminance distribution and become ideal parallel rays. Appropriate alignment characteristics can be obtained by optical treatment. In addition, when the light emitting diodes 1 used are of a plurality of light emitting colors mixed appropriately on the spherical surface 5, and when switching is performed, it is possible to display a multicolor display with uniform light distribution, and the light emitting diodes 1 can be lit at the same time. When doing this, uniform color mixing becomes possible.

(Effect of the invention) As explained above, by arranging a plurality of light emitting diodes as light sources at equal distances from the focal point of the reflecting mirror so that their main optical axes pass through the focal point, the light emitting The diode becomes equivalent to an ideal point light source imagined on the focal point, so that the light source reflected by the reflecting mirror can be an ideal parallel light beam with uniform illuminance distribution. As a result, the light-emitting surface becomes free of light spots, compared to the conventional method, which produces light spots to the extent that the number of light-emitting diodes that are light sources can be clearly distinguished from the outside. The light-emitting surface has an extremely high quality appearance, which has an excellent effect of preventing unnecessary dazzling to the viewer, and furthermore, a plurality of the light-emitting diodes are used, and these are substantially connected to the reflector. Since it is placed at the focal point, the light irradiated to the front lens comes from multiple light emitting diodes, so even if one of them breaks, the light spots caused by it will be minor, so in practical terms, the content of the display will be impaired. This also provides an advantageous effect in terms of safety and the like. Furthermore, the above-mentioned effects can be similarly achieved even when light emitting diodes of two or more colors are used as a light source, both for each color of emitted light and when a mixture of colors is used.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing an embodiment of the lighting device using LED as a light source according to the present invention, Fig. 2 is a cross-sectional view showing the main parts in detail, and Fig. 3 is a cross-sectional view showing a conventional example. It is. 1...Light emitting diode, 2...Front lens, 3
...reflector, 4...focal point, 5...spherical surface, 6...principal optical axis.

Claims (1)

[Scope of utility model registration request] In an illumination device consisting of a paraboloid of revolution and a front lens, at least a single light emitting light is provided on a spherical surface centered on the focal point of the paraboloid of revolution and at a position where the lead-side extension of the main optical axis passes through the focal point. A lighting device characterized in that a plurality of colored light emitting diodes are arranged on the spherical surface including on the front lens side.