JPH0219563B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to various types of floodlights, for example, a floodlight used as a light emitting part of a flash discharge light emitting device for photography.

``Prior Art'' A flash discharge light emitting device used for photography is configured to emit light from a xenon discharge tube through a light emitting window provided in the front of the flash discharge light emitting device.

In such a light emitter, the irradiation angle remains constant due to the almost parabolic cross-section reflector with a xenon discharge tube fixed inside, but the irradiation angle changes depending on telephoto shooting or wide-angle shooting. Some devices have a configuration in which a changing lens is provided in front of the light emitting window.

9 and 10 are cross-sectional views showing the structure of the light emitting part of this type of flash discharge light emitting device, and in these figures, 1 is a body, 2 is a xenon discharge tube,
3 is a reflecting mirror, and 4 is a lens forming a light emitting window. In the conventional example shown in FIG. 9, the illumination angle changing lens 5
(telephoto irradiation lens or wide-angle irradiation lens) is removably installed in front of the light emitting window.
In the conventional example shown in FIG. 10, the illumination angle changing lens 6 is slidably provided on the body 1 so as to move forward and backward in front of the light emitting window.

"Problems to be Solved by the Invention" In the case of the conventional example shown in FIG. There is the inconvenience of having to carry it with you. In the conventional example shown in FIG. 10, it is sufficient to move the illumination angle changing lens 6 forward or backward in accordance with telephoto shooting or wide-angle shooting, and there is no inconvenience as described above, but since this lens 6 has a zoom structure, it is small. This makes it difficult to equip a flash discharge light emitting device.

Furthermore, in the conventional examples shown in FIGS. 9 and 10, the lenses 5 and 6 for changing the illumination angle cannot be used for interchangeable lenses of compact cameras.

"Means for Solving the Problems" The present invention was developed with the aim of solving the above-mentioned problems.In a projector in which a light source is fixed to the inner part of a main reflecting mirror having a concave curved surface,
A sub-reflector is provided with one surface having a planar mirror surface and the other surface a curved mirror surface, and one surface and the other surface are selectively opposed to the light source, so that the sub-reflector is closer to the light source. A projector is proposed in which the projector is rotatably provided within the main reflecting mirror located outside, and the sub-reflecting mirror is rotated to change the light projection range.

At present, small cameras have been developed that have a built-in flash discharge light emitting device and can switch the photographing lens to telephoto shooting or wide-angle shooting. Therefore, the illumination angle can be switched according to telephoto shooting or wide-angle shooting.

Note that the present invention is not limited to being applied to the light emitting part of a flash discharge light emitting device, but is effective when being applied to various types of floodlights.

``Example'' Next, examples in which the present invention is implemented as a light emitting part of a flash discharge light emitting device will be described with reference to the drawings. Figure 1 is a perspective view of the light emitting section, and Figure 2 is a perspective view of the light emitting section.
It is an enlarged sectional view taken along the line A-A in the figure.

In these figures, 11 is a xenon discharge tube,
Reference numeral 12 is a reflecting mirror, and the xenon discharge tube 11 lies deep inside the reflecting mirror 12, which has a substantially parabolic cross section.
Both end portions are side surfaces 12a and 12b of the reflecting mirror 12.
It is fixed via a bushing.

Reference numeral 13 denotes a movable reflecting mirror for changing the irradiation angle, which is made of a long and thin plate shape, and one side 13a of this is a flat mirror surface.
The other surface 13b is formed into a bulged curved mirror surface or a matte surface, and a support shaft 14 is provided at both ends, and the support shaft 14 is rotatable to the side surfaces 12a and 12b of the reflecting mirror 12. By inserting the shaft into
A movable reflecting mirror 13 is rotatably attached.

By rotating the support shaft 14, the movable reflecting mirror 13 can be moved from one side to the other, as shown in FIGS. 3a and 3b.
The configuration is such that the position where a is directly opposed to the xenon discharge tube 11 and the position where the other surface 13b is directly opposed to it are switched.

Then, as shown in FIG. 3a, the movable reflecting mirror 13
When one surface 13 a directly faces the xenon discharge tube 11 , the light emitted from the xenon discharge tube 11 is firstly reflected by the movable reflecting mirror 13 and then secondarily reflected by the reflecting mirror 12 so that the light emitted from the xenon discharge tube 11 is irradiated as parallel light 15 . The distance between the xenon discharge tube 11 and the bottom surface of the reflecting mirror 12 and the position of the movable reflecting mirror 13 are set so that

With this configuration, by switching the movable reflecting mirror 13 as shown in FIG. is diffused light 1
It is irradiated as 6.

Next, the principle of the present invention will be optically explained using FIGS. 4 and 5.

FIG. 4 assumes that the reflecting mirror 12 is formed as a parabolic cross section, and the upper half of the mirror is drawn as a curve 17. When the focal point of the curve 17 is at point P, y ² =4px.

In this figure, when the light source is placed at point P, the light reflected by the reflecting surface (curve 17) is parallel light 15
becomes.

When the light source is moved to the right side (O side) from point P, the light becomes diffused as shown by the dotted line in the diagram, and conversely, when the light source is moved from point P to the left side (+ side), the light is diffused. If you change it to , the light will be focused.

The present invention changes the irradiation area based on the above-mentioned optical principle, and is characterized by the use of a movable reflecting mirror instead of moving the light source.

FIG. 5 is an explanatory diagram showing the reflection state of the movable reflecting mirror 13 shown in the above embodiment, where point A is the center point of the curve 18 corresponding to the other surface 13b, point D is the light source position,
Point B is a mirror image point with the straight line 19 corresponding to the surface 13a as the base line. Point C is on the other side 13b (curve 18)
As can be seen from geometric optics,
The coordinate point is - from (1/a) + (1/b) = (2/R)
(6/7).

Here, if point B is at the same position as point P in FIG. 3, using one surface 13a (straight line 19),
This is the same as if the light source were placed at point P in FIG. 4, resulting in parallel light.

Moreover, when the other surface 13b (curve 18) is used,
This is the same as if the light source were placed at point C in Fig. 5, so in Fig. 4 it is equivalent to the light source moving to the right side (O side) from point P, and by using the reflection of the other surface 13b. The light becomes diffused.

As can be seen from the above, one side 1 of the movable reflecting mirror 13
3a to directly face the xenon discharge tube 11, it becomes parallel light 15, and by switching the other surface 13b to face directly, it becomes diffused light 16.
Movable reflector 13 for standard photography or telephoto photography
By rotating , standard light emission (diffuse light irradiation) or telephoto light emission (parallel light irradiation) is achieved.

The movable reflector 13 is rotated by rotating a support shaft 14 through an interlocking mechanism such as a drive lever or a gear, but it can also be rotated manually or when photographing with a camera equipped with a flash discharge light emitting device. It can be rotated in conjunction with the movement of the lens.

Further, when carrying out the present invention, it is preferable to form a curved surface portion 12c centered on the xenon discharge tube 11 on the bottom surface of the reflecting mirror 12, as shown in FIG.

By forming this curved surface portion 12c in accordance with the viewing angle θ of the movable reflecting mirror 13, the influence of switching of the movable reflecting mirror 13 on the light directly directed from the xenon discharge tube 11 to the curved surface portion 12c is reduced,
The effect of switching the irradiation area can be increased.

FIG. 7 shows another embodiment of the present invention in which a movable reflecting mirror 20 is formed of an elongated curved plate, with both front and back surfaces mirror-finished and configured to rotate as shown in FIGS. 7a and 7b. In this embodiment, by appropriately setting the curved surface of the reflecting mirror 12, its position, the distance between the xenon discharge tube 11 and the bottom surface of the reflecting mirror 12, etc., the irradiation area can be switched in the same manner as in the above embodiment. .

Figure 8 shows three surfaces 21a and 21 with different reflection conditions.
A movable reflecting mirror 21 having mirror surfaces of b and 21c is shown. This movable reflecting mirror 21 is rotatably mounted inside the reflecting mirror 12 in the same manner as in the above embodiment, and the mirror surface 21 is
a, 21b, 21c are each xenon discharge tube 11
Configure it so that it faces directly.

According to this embodiment, by arranging the mirror surface 21a directly facing the xenon discharge tube 11, standard irradiation is achieved by parallel light, by arranging the mirror surface 21b directly facing the xenon discharge tube 11, wide-angle irradiation is achieved by diffused light, and by directly facing the mirror surface 21c, by irradiating with diffused light, standard irradiation is achieved. The irradiation area can be switched in three stages to achieve telephoto irradiation by condensing light.

"Effects of the Invention" As described above, in the present invention, the sub-reflector, which has one surface as a flat mirror surface and the other surface as a curved mirror surface, can be rotated within the main reflector so as to face the light source. Since it is installed at
The present invention can also be implemented satisfactorily with small projectors. In particular, it can be implemented as a light emitting part of a flash discharge light emitting device built into a camera, and is advantageous in that the irradiation area can be switched depending on telephoto shooting or wide-angle shooting.

[Brief explanation of drawings]

The drawings show an example in which the present invention is implemented as a light emitting part of a flash discharge light emitting device used for photography. Fig. 1 is a perspective view of the light emitting part, and Fig. 2 is an enlarged cross-sectional view taken along line A-A in Fig. 1. , FIGS. 3a and 3b are simplified partial enlarged views of the light emitting section showing the switching state of the irradiation area, FIGS. 4 and 5 are diagrams for explaining the principle of the present invention, and FIG.
The figure is a simplified partial enlarged view showing the shape of the bottom surface of the reflector.
Figures 7a and b are simplified diagrams of a light emitting unit showing another embodiment, Figure 8 is a sectional view of a movable reflector having three mirror surfaces with different reflection conditions, and Figure 9 is a movable reflector for changing the irradiation angle that can be attached freely. FIG. 10 is a sectional view showing a light emitting part of a conventional flash discharge light emitting device equipped with a lens, and FIG. 10 is a sectional view of the light emitting part similar to FIG. 9, which is equipped with a slidable lens for changing the irradiation angle. 11...Xenon discharge tube, 12...Reflector, 1
3...Movable reflecting mirror, 13a...One surface (mirror surface), 1
3b...Other surface (mirror surface), 14...Spindle, 20,2
1...Movable reflecting mirror, 21a, 21b, 21c...
Mirror surface.

Claims (1)

[Scope of Claims] 1. In a projector in which a light source is fixed to the inner part of a main reflecting mirror having a concavely curved surface, a sub-reflecting mirror having one surface as a flat mirror surface and the other surface as a curved mirror surface is provided. and the sub-reflector is rotatably provided within the main reflector located outside of the light source with one surface and the other surface selectively facing the light source, and the sub-reflector is rotated. A projector configured to change the projection range by changing the projection range. 2 A xenon discharge tube is fixed to the back of a reflector with an almost parabolic cross section, and a long movable reflector with a flat mirror surface on the front surface and a curved mirror surface on the back surface is placed near the opening of the reflector relative to the xenon discharge tube. 2. A projector according to claim 1, which is rotatably provided parallel to a xenon discharge tube and is implemented as a light emitting part of a flash discharge light emitting device for photography.