JPS6235067Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an illumination device for a close-up camera that uses an accessory to prevent harmful reflected light from a subject and obtain uniform illumination.

Generally, in close-up cameras that only take pictures of subjects at or near the same magnification, a ring strobe is attached to the outer periphery of the photographic lens to illuminate the subject evenly and to prevent harmful shadows from appearing. .

This type of lighting method is suitable for normal subjects with uneven surfaces, but when the subject is flat and especially glossy, such as when copying documents, the light from the ring strobe may be reflected by the subject. Then, the primary reflected light passes through the photographic lens and forms an image on the film surface, producing a harmful annular bright area.

FIG. 1 shows the photographing state of such a conventional close-up camera, in which a glossy flat object 4 illuminated by a ring strobe 3 attached to the outer circumference of the photographing lens 2 of the close-up camera 1 is An image is formed on the film surface 5 by the photographic lens 2, and after being reflected by the annular surface 4a of the subject 4, the light flux shown by A in the figure passes through the photographic lens 2 and onto the film surface 5 as primary reflected light A'. An annular harmful bright area 5a is formed as an image, resulting in a photograph as shown in FIG.

In order to prevent the occurrence of such harmful bright areas 5a, a method of arranging a diffuser plate in front of the ring strobe 2 can be considered, but as the illuminance decreases, the range of the harmful bright areas only becomes wider and the effect is reduced. Almost unrecognized.

This idea was made to solve this problem.A U-shaped board with an expanded tip is attached to the outer periphery of the photographing lens from which the ring strobe of a close-up camera is removed. A ring strobe and a reflector are installed diagonally on two sides of the object, each facing toward the subject. Place the camera lens so that it is approximately symmetrical with respect to the optical axis.
The present invention provides an illumination device for a close-up camera that prevents harmful reflected light.

Hereinafter, an embodiment of this invention will be described with reference to FIG. 3 of the accompanying drawings.

The ring strobe 3 of the close-up camera 1 shown in FIG. do.

The removed ring strobe 3 is installed diagonally toward the subject on one expanded side of the board 6, and its position is the first critical optical path A where the primary reflected light from the subject 4 of the ring strobe 3 enters the screen. ₁ , so that it is on the outside with respect to the optical axis C of the photographing lens 2.

Furthermore, on the other side of the substrate 6 that is approximately symmetrical to the ring strobe 3 with respect to the optical axis C of the photographic lens, that is,
A second critical optical path symmetrical to the first critical optical path _A1 above.
A reflecting mirror 7 is installed diagonally outward from A ₂ with respect to the optical axis C of the photographing lens to reflect the light from the ring strobe 3 toward the subject 4.

Note that the reflecting mirror 7 is desirably provided slightly closer to the optical axis C than the ring strobe 3 in order to effectively and powerfully irradiate the subject 4 with its reflected light.

According to this lighting device, the light beam emitted from the ring strobe 3 illuminates the subject 4 diagonally from the front right side, but a portion of it is reflected by the reflector 7 and illuminates the subject 4 diagonally from the front left side. do.

Here, in a camera dedicated to close-up photography, the distance between the photographing lens 2 and the subject 4 is always constant, so by appropriately selecting the positions and angles of the ring strobe 3 and the reflector 7, the subject can be photographed from both the left and right front. 4 can be uniformly illuminated.

In this case, since both the ring strobe 3 and the reflecting mirror 7 are located outside the first and second limited optical paths A ₁ and A ₂ with respect to the optical axis C of the photographing lens, the ring strobe 3 and the reflecting mirror 7 are located outside the subject 4. 1 reflected by
The second reflected light does not directly enter the photographic lens 2.

Furthermore, even if some of the reflected light near the limited optical path enters the photographing lens 2, the reflected light forms an image outside the photographic screen, so that the reflected image does not enter the screen.

Note that the ring strobe 3 and the reflector 7 are located to the side of the close-up camera 1, and the subject 4 is illuminated from an oblique direction, but since the subject 4 is flat, no shadow is produced.

Further, when photographing a normal subject having unevenness, by removing the ring strobe 3 from the substrate 6 and attaching it to the outer periphery of the photographing lens 2, uniform illumination without shadows can be achieved.

As described above, according to this invention, when copying a flat object such as a document using a close-up camera with a ring strobe, the ring strobe is removed from the close-up camera and the flat object is placed on the outer periphery of the photographing lens. A U-shaped board with an enlarged tip is attached as an accessory for photographing images, and a ring strobe and a reflector are each diagonally placed on the two enlarged sides of the board, facing the subject. , both of them are arranged at approximately symmetrical positions with respect to the optical axis of the photographing lens, which is outside the critical ray where the primary reflected light from the light source by the planar subject enters the screen, thereby eliminating harmful annular reflections that occur on the film surface. It has the excellent effect of completely preventing images and providing uniform illumination of the entire screen with a single ring strobe.

[Brief explanation of the drawing]

Fig. 1 is an optical path diagram showing how a planar object is photographed using a conventional close-up camera, Fig. 2 is an explanatory diagram showing a photographic screen taken in the state shown in Fig. 1, and Fig. 3 is a diagram based on this invention. FIG. 3 is an optical path diagram showing a state in which a planar object is photographed by a close-up camera using an illumination device. 1... Close-up camera, 2... Photography lens, 3...
Ring strobe, 4...Planar subject, 5...Film surface, 6...Substrate, 7...Reflector.

Claims (1)

[Scope of utility model registration request] This is an illumination device for photographing a flat object using a close-up camera with a ring strobe attached to the outer periphery of the photographing lens. Attach the board, and on one side of the board expanded,
The removed ring strobe is installed diagonally toward the subject, and a reflector that directs the light from the ring strobe toward the subject is diagonally installed on the other side of the substrate that is approximately symmetrical with respect to the optical axis of the photographing lens. The ring strobe and the reflecting mirror are located outside of the first and second limiting optical paths A ₁ and A ₂ through which the primary reflected light from the planar object enters the screen, with respect to the optical axis of the photographing lens. Close-up camera lighting device.