JPS6022494Y2 - spot light - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a spotlight, and more specifically, to a lensless spot whose irradiation diameter can be adjusted using a parabolic reflector, which is mainly used for stage lighting.

This is the first conventional lensless spotlight of this kind.
An optical configuration as shown in Figure a has been put into practical use.

To explain the optical principle based on FIG. 1a, the light source 1
Among the light fluxes emitted from the light source, the light fluxes emitted forward are reflected by the spherical reflecting mirror 2 centered on the optical center of the light source 1, such as a light ray 5'', and after condensing in the vicinity of the light source 1, the light flux emitted from the light source 1 The light beam enters the parabolic reflector 3 together with the light beam emitted directly backward.

The parabolic reflecting mirror 3 can be moved forward and backward while maintaining its axis on the optical axis, and when moved to the rearmost position, its focal point coincides with the position of the light source 1, as shown in FIG. 1a.

At this time, the light beam incident from the optical center of the light source 1 is reflected by the parabolic reflector 3, for example, as a light ray 5, and is projected forward as a light beam parallel to the optical axis 4, as a light ray 5'.

By the way, an actual light source is not a point light source, but can be regarded as a surface light source with a certain size, but the light flux incident from outside the optical center is reflected by the parabolic reflector 3, for example, as rays 6 and 7. Then, the light beams 6' and 7' are projected forward with respect to the optical axis 4 as a converging and diffusive light beam.

In front of the illuminated surface, light is projected with a size approximately determined by the size of the light source 1, the focal length of the parabolic reflector 3, and the distance from the light source 1 to the illuminated surface.

At this time, the light distribution is the brightest at the center of the irradiation surface and the irradiation diameter is the smallest, as shown in FIG. 5A.

When the parabolic reflector 3 is moved forward (towards the light source) from the state shown in FIG. 1a, the light flux incident from the optical center of the light source 1 becomes
The light is reflected by the parabolic reflector 3 and projected forward as a diffuse light flux toward the optical axis 4, and the light that enters from outside the optical center is reflected by the parabolic reflector 3. The converging light flux decreases and the diffuse light flux increases.

At this time, the light distribution is such that the central illuminance of the irradiation surface decreases and the irradiation diameter increases, as shown at the beginning of FIG.

Furthermore, when the parabolic reflector 3 is moved to the relevant position as shown in FIG. , 10' are all projected forward as a diffusive light beam with respect to the optical axis 4.

Incidentally, a luminous flux such as ray 8 emitted from the optical center is ray 8
Needless to say, it is a diffuse luminous flux that is projected as shown in FIG.

Of course, such a light distribution is not practical, but in the previous stage, that is, in the state where the parabolic reflector 3 is positioned a little further away from the light source 1 than shown in Figure 1, the light distribution as shown in Figure 5 is possible. As shown in Fig. 8, the light distribution is extremely dark at the center compared to the illumination at the periphery of the irradiated surface, resulting in a so-called drop-off state, which also poses a practical problem.

Therefore, although lensless spotlights have the characteristics of no color aggregation and are lightweight compared to plano-convex lens spotlights, they can irradiate light that can maintain a practical light distribution as described above. The reality is that it is not widely used because the adjustment range of the diameter is small.

This idea was made by focusing on these conventional problems, and it uses a parabolic reflector placed opposite the light bulb.
Consisting of a parabolic reflector (1) having an opening in the center, and a second parabolic reflector whose outside diameter is the inner diameter of the center opening of the reflector, and the relative position of the reflector group and the light bulb. is adjustable, and the light center of the light bulb is placed near the focal point of the first parabolic reflector, and the second parabolic reflector maintains its axis on the optical axis and can be adjusted back and forth. As a result, even when the irradiation diameter is expanded, the so-called drop-out phenomenon does not occur, and the adjustment range of the irradiation diameter that can maintain a practical light distribution can be greatly expanded.The aim is to solve the above problems. It is said that

This invention will be explained below based on the drawings.

FIG. 2 is a sectional view showing an embodiment of the lensless spotlight according to the present invention.

To explain the configuration first, the spotlight includes a light bulb 11,
Spherical reflector 12, spherical reflector holder 13, socket 1
4. First parabolic reflecting mirror 15, second parabolic reflecting mirror 16, longitudinal adjustment shaft 17 of the second parabolic reflecting mirror 16, adjustment shaft 17
The handle handle 18 attached to the handle, the guide 19 for the adjustment shaft 17, the power cord 20, the color filter differential frame holder 21, the lamp body 2
2. It is composed of an arm 23, etc., and the position of the second parabolic reflector 16 can be adjusted by holding the grip handle 18 and sliding the longitudinal adjustment shaft 17 with respect to the guide 19 in the longitudinal direction; The irradiation diameter of the projected light beam can be changed.

The first parabolic reflecting mirror 15 has a ring shape, the inner diameter of the central opening matches the outer diameter of the second parabolic reflecting mirror 16, and is installed with the light center of the light bulb 11 as the focal point.

Below, the principle of the optical system of the above-mentioned spotlight is shown in Figure 3a.
, b will be explained.

Of the luminous flux emitted from the bulb 11, the luminous flux emitted forward is reflected by the spherical reflector 12 centered on the light center of the bulb 11, for example as a ray 24', and after condensing in the vicinity of the bulb 11, the light beam 24' The light beam enters the first parabolic reflecting mirror 15 or the second parabolic reflecting mirror 16 together with the light beam emitted directly backward.

The luminous flux incident on the first parabolic reflector 15 from the light bulb 11 is
The light is reflected by the reflecting mirror 15 and projected forward as a light beam approximately parallel to the optical axis 4, and the light distribution is such that the center of the irradiation surface is bright and the irradiation diameter is small, as shown in FIG. 4a.

The second parabolic reflector 16 can be moved forward and backward while keeping its axis on the optical axis 4, and when moved to the rearmost position, the focal point is at the position of the light bulb 11, as shown in FIG. 3a. Match.

At this time, the light beam entering the second parabolic reflector 16 from the light bulb 11 is reflected by the reflector 16 and projected forward as a light beam approximately parallel to the optical axis 4, as shown in FIG. As shown in A, it overlaps with the center of the irradiated surface by the first parabolic reflecting mirror 15.

This is an example shown in FIGS. 3a and 3b, where the focal length of the first parabolic reflector 15 is shorter than that of the second parabolic reflector 16, so the light bulb 11 is This is because the difference in the projected light beams becomes larger when placed at the focal position of each parabolic reflector 15, 16.

When the second parabolic reflector 16 is moved forward from the above state, the convergent light flux of the light reflected by the reflector 16 with respect to the optical axis 4 decreases, the diffuse light flux increases, and the diffusion angle increases. is larger, the diameter of the irradiation by the second parabolic reflector 16 increases,
It approaches, matches, and becomes even larger than the irradiation diameter by the first parabolic reflecting mirror 15.

Along with this, in the light distribution of the second parabolic reflector 16, the proportion of the light amount in the central part decreases as shown in FIG. Since this is supplemented by the irradiation from the reflecting mirror 15, the central portion does not become dark as a whole, as shown by the mouth in FIG. 4C.

The second parabolic reflector 16 is further moved forward, and as shown in FIG. Assuming that the light rays 26' near the inner circumference of the reflected light are approximately parallel to each other,
The light distribution of the irradiation by the second parabolic reflector 16 is completely absent in the central part as shown in Fig. It is supplemented by the irradiation from the mirror 15, and the irradiation diameter can be expanded without darkening the central part as shown by 8 in FIG.

In the above explanation, all the light beams emitted directly forward from the light bulb are returned to the light bulb position using a spherical reflector, but if the direct light is blocked with a louver, etc., or the direct light is directly projected forward as diffused light. It goes without saying that even in this case, the effects of the optical system according to the present invention can be achieved without any change.

Also, the first parabolic reflector has been explained with its focal point fixed at the light center position of the light bulb, but it would be possible to make it slightly adjustable back and forth in order to adjust the aperture angle at the minimum aperture. , a more versatile lensless spotlight can be provided.

Furthermore, in the above explanation, in order to adjust the relative position between the parabolic reflector and the light bulb, the light bulb, the spherical reflector, and the first parabolic reflector are fixed, and the second parabolic reflector is adjustable by moving back and forth. However, in the opposite form, that is, by fixing the second parabolic reflector, the light bulb,
It goes without saying that the effects of the present invention can be expected even if the three components, the spherical reflector and the first parabolic reflector, can be adjusted forward and backward as a unit.

As explained above, the lensless spotlight of the present invention includes a parabolic reflector disposed facing the light bulb, a first parabolic reflector having an opening in the center, and a first parabolic reflector having an opening in the center; and a second parabolic reflector whose outside diameter is the inner diameter of the central opening of Because the axis can be adjusted back and forth while keeping the axis on the optical axis, the second parabolic reflector can be moved away from the light bulb to focus the emitted light flux, and it can also be moved closer to the light bulb to focus the emitted light flux. Even when the light is diffused, the irradiation by the first parabolic reflector is supplemented, and it is possible to obtain a light distribution without the drop-off phenomenon.

Therefore, it is possible to provide a lensless spotlight that can significantly expand the adjustment range of the irradiation diameter while maintaining a practical light distribution.

[Brief explanation of the drawing]

Figures 1a and b are diagrams showing the optical principle of a conventional lensless spotlight, Figure 2 is a sectional view showing an embodiment of the lensless spotlight according to the present invention, and Figures 3a and b are diagrams showing the optical principle of a conventional lensless spotlight. A diagram showing the optical principle of a lensless spotlight,
Figures 4a, b, and c are explanatory diagrams of light distribution of the lensless spotlight according to the present invention; Figure 4a is an explanatory diagram of light distribution by the first parabolic reflector; FIG. 4C is an explanatory diagram of light distribution using an object surface reflector, FIG. 4C is an explanatory diagram of light distribution using synthetic leather, and FIG. In the figure, 11: light bulb, 15: first parabolic reflector, 16: second parabolic reflector.

Claims (1)

[Scope of utility model registration request] A light bulb, a first parabolic reflector having an opening in the center, a second parabolic reflector whose outside diameter is the inner diameter of the center opening of the reflector, and the relative position of the reflector group and the light bulb. The light center of the light bulb is placed near the focal point of the first parabolic reflector, and the second parabolic reflector maintains its axis on the optical axis and rotates forward and backward. A spotlight characterized by being adjustable.