JPH0577050B2 - - 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.

8 and 9 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, and 3 is a
4 is a reflecting mirror, and 4 is a lens forming a light emitting window.
In the conventional example shown in FIG. 8, a lens 5 for changing the irradiation angle (telephoto irradiation lens or wide-angle irradiation lens) is removably provided in front of the light emitting window.
In the conventional example shown in the figure, 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. 8, the lens 5 for changing the illumination angle must be attached each time for telephoto shooting or wide-angle shooting, and this lens 5 must be carried. However, there are inconveniences such as the possibility of losing the lens 5.

In the conventional example shown in FIG. 9, the lens 6 for changing the illumination angle can be moved forward or backward according to telephoto shooting or wide-angle shooting, and there is no inconvenience as described above. However, since this lens 6 has a zoom structure, it is small. This makes it difficult to equip a flash discharge light emitting device.

Further, in the conventional examples shown in FIGS. 8 and 9, the illumination angle changing lenses 5 and 6 cannot be used for lens exchange of a compact camera in which lenses can be exchanged.

"Means for Solving the Problems" The present invention was developed with the aim of solving the above-mentioned problems, and includes a long and thin light source such as a xenon discharge tube fixed to the deep part of a reflecting mirror with an almost parabolic cross section. In the projector, the reflecting mirror is formed with a first mirror surface and a second mirror surface in which reflection conditions are different between the mirror surface portion on one side and the mirror surface portion on the other side parallel to the light source, and the mirror surface is parallel to the light source. is provided with a long light-shielding plate that partially surrounds the light source in the longitudinal direction and rotates around the longitudinal direction of the light source. The present invention proposes a light projector equipped with a variable irradiation angle mechanism, characterized in that it is configured to selectively project light onto either one of the second mirror surfaces.

Currently, 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 denotes a reflecting mirror, and the xenon discharge tube 11 is placed in the inner part of the reflecting mirror 12 having a substantially parabolic cross section, and its both ends are fixed to side surfaces 12a and 12b of the reflecting mirror 12 via bushings.

Further, the reflecting mirror 12 is a mirror surface on the upper and lower sides of the xenon discharge tube 11, that is, a mirror surface 12c above the base line 13.
The curvatures of the lower mirror surface 12d and the lower mirror surface 12d are changed so that the reflection conditions on these mirror surfaces are different. In addition,
Details regarding this point will be described later.

Reference numeral 14 denotes a light shielding plate for changing the irradiation angle, which is formed into an elongated gutter shape, and its inner surface 14a is mirror-finished, and a support shaft 15 is provided at both ends, and this support shaft 15 serves as a reflecting mirror. The guide holes 12e and 12f formed in the side surfaces 12a and 12b of the mirror 12 are penetrated to project outside the reflecting mirror.

The guide holes 12e and 12f are as shown in the figure.
This is an arc-shaped hole whose concentric point is the center point of the cross section of the xenon discharge tube 11.
By driving along the xenon discharge tube 11, the light shielding plate 14 is displaced above or below the xenon discharge tube 11.

FIGS. 3a and 3b show the state of irradiated light when the position of the light shielding plate 14 is changed to switch the irradiation angle. As can be seen from FIG. 3a, when the light shielding plate 14 is positioned below the xenon discharge tube 11, the light emitted from the xenon discharge tube 11 to the lower mirror surface 12d is blocked, and the light is emitted only from the upper mirror surface 12c. Upper mirror surface 12
If c is formed into a parabolic shape and the xenon discharge tube 11 is positioned at the focal point, the reflected light becomes parallel light 16 as shown in the figure.

As shown in FIG. 3b, when the light shielding plate 14 is moved above the xenon discharge tube 11, the light emitted from the xenon discharge tube 11 is projected only onto the lower mirror surface 12d.
Diffused light 1 whose reflected light follows the curvature of the mirror surface 12d
It becomes 7.

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 mirror surface 12c is curved 18,
FIG. 3 is an explanatory diagram depicting a lower mirror surface 12d as a curved line 19; Note that the description will be made assuming that the curve 18 is a parabola having a focal point at position P ₁ , the curve 19 is a parabola having a focal point at position P ₂ , and the light source is located at position P ₁ .

When the reflecting mirror 12 is formed into a curved surface as described above, the reflection of light from the light source by the upper mirror surface 12c becomes parallel light 1.
6, and the reflection of the light by the lower mirror surface 12d becomes diffused light 17 as shown in the figure.

The diffused light 17 has an angle of θ ₁ with respect to the parallel light 16a generated as reflected light from the lower mirror surface 12d, assuming that the light source is at position _P2 . This angle θ ₁ is equal to the angle θ ₂ of ∠P ₁ QP ₂ , where Q is the reflecting part.

The irradiation angle θ ₁ has the characteristics shown in FIG. 5 by changing the X coordinate of the reflecting portion Q.
That is, FIG. 5 is a graph in which the horizontal axis represents the X coordinate shown in FIG. 4, the vertical axis represents the irradiation angle θ ₁ , and the changes in the irradiation angle θ ₁ are plotted.

As can be seen from this graph, an irradiation angle of 16° can be obtained with the mirror surface 12d having a parabolic cross section according to the conditions shown in FIG.
The area of the irradiated light on the lower mirror surface 12d is expanded compared to the irradiated light on the lower mirror surface 12d.

As can be seen from the above, when the light shielding plate 14 is moved below the xenon discharge tube 11 and reflected by the upper mirror surface 12c, the light becomes parallel light 16, and when the light shielding plate 14 is moved above the xenon discharge tube 11, the lower When reflected by the mirror surface 12d, it becomes diffused light 17, so by switching and moving the light shielding plate 14 according to standard photography or telephoto photography,
Standard light emission (diffuse light irradiation) or telephoto light emission (parallel light irradiation).

The light shielding plate 14 is switched and moved by driving the spindle 15 through an interlocking mechanism such as a drive lever or a gear, but it is configured to be switched manually, and it is not possible to take pictures using a camera with a built-in flash discharge light emitting device. It can be switched and moved in conjunction with the movement of the lens.

In the above embodiment, the mirror surface 12d that becomes the diffused light 17
is formed on the lower side of the reflecting mirror 12, so that the diffused light 1
As shown in FIG. 6, the main axis 20 of the lower mirror surface 12d is appropriately tilted, and the mirror surface 12d is bent from the tentative line 21 shown in the figure to the solid line. Then, reflector 12
It is possible to correctly illuminate the front direction of the camera. Further, if a prism or the like for correcting the diffused light 17 in the front direction is provided at a position in front of the reflecting mirror 12, there is no need to tilt the main shaft 20 as in the above embodiment.

FIG. 7 shows an application example of the present invention using the light shielding plate 14 described above. This application example is characterized in that the upper mirror surface 22a and the lower mirror surface 22d of the reflecting mirror 22 have substantially parabolic cross sections with the same curvature, and a lens 23 that can change the irradiation angle is provided in front of the reflecting mirror 22. be.

The lens 23 corrects the light passing through the lower half 23d in a wider angle than the upper half 23a, and in this applied example, the same effect as in the above embodiment can be obtained by switching and moving the light shielding plate 14.

In addition to the above-mentioned embodiments, the present invention can be implemented as follows.

(1) The upper mirror surface and the lower mirror surface are formed with the same curvature, and one of the lower or upper mirror surfaces has a satin surface.

(2) Contrary to the above embodiment, the upper mirror surface 12c is formed as a reflection surface for the diffused light 17, and the lower mirror surface 12d is formed as a reflection surface for the parallel light 16.

(3) Since the light-shielding plate 14 only needs to have a light-shielding effect, the inner surface 14a does not necessarily need to be mirror-finished.

(4) In the above embodiments, a reflecting mirror having a substantially parabolic cross section has been described, but the same can be applied to a reflecting mirror having an elliptical cross section or a hyperbolic cross section.

"Effects of the Invention" As described above, in the present invention, a reflecting mirror having a light source therein has a first mirror surface and a second mirror surface having different reflection conditions.
a mirror surface, and the light emitted from the light source is
Since a light shielding member is provided to project light onto either the mirror surface or the second mirror surface, the irradiation angle can be easily changed by switching and driving the light shielding member, and it can also be implemented satisfactorily with small projectors. can do.

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 the drawing]

Figures 1 to 6 show examples in which the present invention is implemented as a light emitting part of a flash discharge generator used for photography. Figure 1 is a perspective view of the light emitting part, and Figure 2 is a -A-line enlarged sectional view; Figures 3a and 3b are simplified diagrams of the light emitting section showing the state of switching the illumination angle; Figures 4 and 5 are diagrams for explaining the principle of the present invention; Figure 6; 7 is a simplified partial diagram of an embodiment in which the main optical path direction of the diffused light is corrected, FIG. 7 a, b is a simplified diagram similar to FIG. 3 a, b showing an application example of the present invention, and FIG. FIG. 9 is a sectional view showing a light emitting part of a conventional flash discharge light emitting device equipped with a lens for changing the angle of illumination, and FIG. 9 is a sectional view of the light emitting part similar to FIG. 11...Xenon discharge tube, 12...Reflector, 1
2c... Upper mirror surface, 12d... Lower mirror surface, 12
e, 12f... Guide hole, 14... Light shielding plate, 14a
...Inner surface (mirror surface), 15...Spindle.

Claims (1)

[Scope of Claims] 1. In a projector in which an elongated light source such as a xenon discharge tube is fixed to the deep part of a reflecting mirror having a substantially parabolic cross section, the reflecting mirror has a mirror surface on one side parallel to the light source and a mirror surface on the other side. forming a first mirror surface and a second mirror surface with mutually different reflection conditions, and
The light source is provided with a long light shielding plate that partially surrounds the light source along its longitudinal direction and is rotated around the longitudinal direction of the light source. A light projector equipped with a variable irradiation angle mechanism, characterized in that it is configured to selectively project light onto either one of a first mirror surface or a second mirror surface. 2. A xenon discharge tube is fixed to the deep part of a reflecting mirror with an almost parabolic cross section, and the curvature of the mirror surface on one side and the mirror surface on the other side of the reflector parallel to the xenon discharge tube is changed to provide different reflection conditions. 1st mirror surface and 2nd mirror surface
Claim 1: A gutter-shaped light-shielding plate with a mirror surface formed on the inside is provided so as to be rotatable around the longitudinal direction of a state xenon discharge tube, and is implemented as a light emitting device of a flash discharge light emitting device for photography. A floodlight equipped with a variable illumination angle mechanism as described in Section 1.