JPH03153226A - Projection device - Google Patents

Abstract

PURPOSE:To improve the flatness and position accuracy of a film by fixing a slide film with a film pressure plate made of a transparent material when a projection unit is mounted on a camera instead of a rear cover unit. CONSTITUTION:A projection unit 18 consisting of a reflecting mirror 11, an electric bulb 12 as a light source, an infrared-ray cutting filter 13, a condenser lens 14 consisting of a Fresnel lens, and a slide mount 15, holding the slide film F by energizing and fixing the film pressure plate 16 and a film positioning plat 17 which are both made of transparent materials such as glass and acrylic resin with a spring, from the rear to the front in the direction of the optical axis is mounted replacing the rear lid unit of a single-lens reflex camera 21. Thus, the film F is pressed and fixed with the film pressure plate 16 made of the transparent material to improve the flatness and position accuracy of the film F.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a projection device that is detachable from a camera.

<Prior Art> Conventionally, a slide film projection device projects a photograph (slide film) taken with a camera onto a screen using a light source.

FIG. 7 shows a configuration diagram of the optical system of this type of projection device.The light from the light source bulb 2 efficiently illuminates the entire slide film F of the mount 5 by the reflecting mirror 1, but out of the light from the bulb 2,
The infrared light is removed by the infrared cut filter 3, and furthermore, the slide film Ft is efficiently illuminated by preventing the light from spreading by the condenser lens 4. This slide film F is held by its mount portion 5aK, and by supporting the mount portion Sa, the projector can support the entire slide film F at a predetermined position.

And slide film F? The transmitted light passes through a projection lens 6 and forms an image of the slide film F on a screen.

In addition, if the heat generated by the light bulb 2 as a light source is large, the slide film F of the slide mount 5 will curve as shown in the solid line as shown in FIG. The focus position differs between the periphery and the center, making it difficult to focus the entire screen.In order to dissipate this heat to the outside and prevent the projection device from becoming too hot, a cooling fan is used to cool the outside air. The air is pumped into the inside of the seven-projection device, and the hot internal air is exhausted to cool it down.

<Problems to be Solved by the Invention> However, in the conventional slide projector described above, in order to hold the mount portion 5a of the slide film F,
The positional accuracy and flatness of the film are unfavorable, and furthermore, when a film that is not mounted, such as a sleeve film, is used, a special holder or the like is often required.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the conventional example described above, and to provide a projection device with high film flatness and good positional accuracy.

Means for Solving the Problems> To achieve the above object, the present invention provides a projection device in which a projection unit having a slide film support and its illumination system is made detachable by replacing it with a back cover unit of a camera. , the film support section has a film pressure plate made of a transparent material for fixing the film.

In the projection device with the above configuration, when the back cover unit of the camera is replaced with the projection unit, the film is fully pressed and fixed by the film pressing plate made of transparent material, so the flatness of the film is high. Therefore, the positional accuracy of the film can also be improved.

<Embodiment> Hereinafter, a first embodiment of the present invention will be explained based on all FIGS. 1 to 3.

Figures 1 and 2 are schematic cross-sectional views of a single-lens reflex camera with an automatic focus adjustment function equipped with a projection unit (instead of the back cover unit shown), and Figure 1 shows the projection unit. FIG. 2 shows the adjusted state when installed. In the figure, the reflector 11 is moved from the rear to the front along the optical axis direction. Light bulb for light source 12. Infrared cut filter 3
, a condensing lens 14 consisting of a 7-lens lens, a film pressure plate 16 and a film positioning plate 17 made of a transparent material such as glass or acrylic resin, each of which is fixed by forward spring bias.
- A projection unit 18 consisting of a held slide mount 15 is attached to replace the back cover unit (not shown) of the eye reflex camera 21. Further, the slide film Fli can be replaced by sliding the entire film pressure plate 16 against the film positioning plate 17.

On the other hand, the eye reflex camera 21 has a photographic lens 22 which also serves as a projection lens on the front side, and a main mirror 23 and a sub-mirror 24 are rotatably disposed behind the photographic lens 22.
A focus detection device 25 facing the sub-mirror 24 is provided at the bottom.
However, there is a pentaprism 2 at the top facing the main mirror 23.
6 are provided respectively, and a rail surface 27a is provided on the rear side.
'&: A shutter curtain 28 is disposed inside the aperture part 27, and a photographing lens 2 is disposed on the front side.
An auxiliary light projecting device 29 for distance measurement is provided on the top of the lens 2.

In this embodiment with the above configuration, the camera 2 shown in FIG.
1, when the projection unit 18 is attached to the auxiliary light projector 29, a pattern is projected onto a screen (not shown), and the reflected light passes through the photographic lens 22 and is sent to the focus detection device by the sub-mirror 24. It leads to 25. Then, based on this focus detection result, all lens driving is performed.
Full focus adjustment is performed, but since the film F is now at a position a predetermined amount lower than when it is used as a camera, it is necessary to fully correct the focus position by this amount. At this time, the shutter curtain 28 blocks the light and sound of the light bulb 12 so that the focus detection device 25 does not malfunction due to the light from the light bulb 12, which is the light source of the projection device. Furthermore, the slide film F includes a film pressure plate 16 and a film positioning plate 1.
7, the rail surface 2 of the camera 21
7a Color slide film Ft distance is guaranteed, and automatic focus adjustment accuracy (flange back) is also guaranteed.

Next, FIG. 2 shows the projection state, and the light of the relic 12 is efficiently irradiated onto the slide film FIR by the reflecting mirror 11, the infrared component is removed by the infrared cut filter 13, and then the light from the relic 12 is efficiently irradiated onto the slide film FIR by the infrared cut filter 13. Light is guided to slide film F. Here, since the condenser lens 14 is not a Fresnel lens, the entire projection apparatus is downsized, but a lens other than a Fresnel lens may be used. Further, in this case, since there is no need for light shielding, the shutter curtain 28 is open, and the main mirror 23 and sub-mirror 24 are also rotated and retreated from the optical path.

Then, the image of the slide film F fixed by the film pressure plate 16 and the film positioning plate 17 is projected onto the screen by the photographing (projection) lens 22. In addition, the infrared cut filter 13 has a light source bulb 120 round 5 power;
If it is not large, the influence on the film and other parts will be reduced by modifying the infrared component, and it can be omitted.
Furthermore, a fan for cooling the entire projection apparatus can also be omitted.

This makes it possible to significantly reduce costs and downsize.

In addition, as for supporting the slide film F, as shown in FIG.
Because flatness is guaranteed by .

The problems caused by the curvature of the slide film F shown in FIG. 8 can be completely prevented.

Furthermore, since the distance δ from the rail surface 27a of the camera 21 to the slide film F does not change, once the -degree focus is fully adjusted, there is no need to readjust it every time the film is replaced, and the automatic focus adjustment function of the camera 21 can be used. When performing focus adjustment, it is only necessary to adjust the focus to a position corrected by this distance δ, so automatic focus adjustment can be achieved easily and at low cost.

Roughly speaking, if the refractive index of the film positioning plate 17 is increased, the apparent distance δ from the rail surface 27a to the film surface can be shortened in terms of optical path length, and the film F can be brought closer to the rail surface 27a. This is particularly effective when it is desired to increase the distance from the projection lens 22 to the screen. Since the film positioning plate 17 covers a portion of the aperture 27 of the camera 21, it is possible to prevent the shutter curtain 28 from being accidentally damaged and dust from entering.

Furthermore, if the aperture part 27 of the camera 21 and the screen of the slide film F are misaligned by a large amount, the screen is vignetted by this amount of deviation, but in this embodiment, the film positioning plate 17 is used to adjust the screen of the slide film F to the aperture part 27. Because positioning can be performed efficiently, accurate positioning can be performed easily.

FIG. 4 shows a second embodiment of the invention.

In order to simplify the explanation, the same parts as those in the first embodiment are given the same reference numerals, and only the different points will be explained.
has a built-in shutter 33, and a part of the aperture 34 on the rear side.
The projection unit 18 is replaced in place of the back cover unit of an autofocus camera which is provided with a rail surface 34a on the front side and an infrared light projecting unit 35 for distance measurement and a light receiving unit 36 on the top and bottom of the front side. It's made to be worn. The structure of the projection unit 18 is the same as that of the first embodiment.

In this embodiment with the above configuration, focus adjustment is performed by projecting infrared light projected from the light projecting unit 35 onto the screen, and receiving the reflected light by the light receiving unit 36 to adjust the distance to the screen. To detect. Then, from this distance information, the focal length of the photographing (projection) lens 32, and the distance from the rail surface 34a to the film surface, the extending position of the photographing lens 32 is calculated, and the lens is driven based on this signal.

Next, the projection of the image on the slide film F is performed using the first method described above.
As in the embodiment, the infrared component of the light from the light bulb 12 is removed by the infrared filter 13, the slide film F is irradiated by the condensing lens 14, and the image of the film F is screened by the photographing lens 32. image on top.

Further, in this embodiment, the film positioning plate 17 does not go deep inside the aperture part 34 of the camera 31, but by making it enter close to the photographing lens 32, the film surface and the rail surface are optically aligned. 34a, it is also possible to omit the correction of the optical path length as in the first embodiment.

This film positioning plate 17 can prevent scratches caused by dust or foreign matter from entering the photographic lens 32 (aperture side), and can also guarantee the flatness of the film, guarantee flange back, and prevent misalignment between the film screen and the aperture. is also possible.

FIG. 5 shows a third embodiment of the present invention.

In this embodiment, a projection unit 18a for a sleeve-shaped slide film Fa in which the slide film is not fixed to a mount is used as a back cover unit of a single-lens reflex camera 21 having an automatic focus adjustment function similar to that of the first embodiment. When installed instead of the slide film pm, the slide film pm is fixed between the rail surface 27a of the aperture part 27 and the film pressure plate 16 made of a transparent material such as glass or acrylic resin. This is the same as the first embodiment described above.

The operation of this embodiment with the above configuration is similar to that of the first embodiment described above, but since the slide film Fa is directly pressed and fixed to the rail surface 27a of the camera 21 by the film pressure plate 16, during normal shooting You can adjust the focus in the same way. At this time, as in the first embodiment, the shutter 28 is
Although it is desirable that the light bulb 12 be in a closed state, it is not necessary if the light bulb 12 is not emitting light.

In this embodiment, since the film positioning plate is omitted, the structure can be simplified, and there is no drop in the amount of light due to the film positioning plate.Furthermore, the film feeding mechanism of the camera 21 allows the slide film pa
This eliminates the need for a special film feeding mechanism.

In addition, the flatness of the film is equivalent to that at the time of photographing, and is higher than that of conventional projection devices.

FIG. 6 shows a fourth embodiment of the present invention.

In this embodiment, similarly to the third embodiment, a slide film that is not mounted δ, that is, a slide film Fa, is used in the projection unit 18a of the back cover unit of an autofocus camera 31 similar to the second embodiment. It was installed instead. Other configurations and operations are described in Section 2 above.
Same as the embodiment 0 In this embodiment as well, the slide film Fa is directly pressed and fixed to the rail surface 34a of the camera 31 by the film pressure plate 16, so focus adjustment can be performed in the same way as in normal photographing.

At the time of projection, the light beam from the light bulb 12 that has passed through the slide film F& is projected onto the screen by the photographing lens 32.

<Effects of the Invention> As explained above, the present invention is such that when the projection unit is attached to the camera instead of the back cover unit, the slide film is fixed by a film pressure plate made of a transparent material, so that the flat surface of the film is fixed. This method has advantages such as improved film positioning accuracy and improved film positioning accuracy, and eliminates the need for a dedicated holder even for sleeve-shaped films.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a projection device attached to a camera according to a first embodiment of the present invention, FIG. 2 is a schematic sectional view during projection, and FIG. 3 is an enlarged sectional view showing the film holding state. 4 is a schematic cross-sectional view of a second embodiment of the present invention, FIG. 5 is a schematic cross-sectional view of a third embodiment of the present invention, FIG. 6 is a schematic cross-sectional view of a fourth embodiment of the present invention, and FIG. This figure is a schematic configuration diagram of a conventional projection apparatus, and FIG. 8 is an explanatory diagram of a curved state of a film during projection in the conventional projection apparatus. 12... Light bulb, 13... Infrared cut filter, 14
...Condensing lens, 15...Slide mount, F.
...Slide film, F&...Sleeve-shaped slide film, 16...Film pressure plate, 17...Fill lh Q '71 deciding plate, 18, 18&...Projection unit, 21.31...Camera , 22.32...
Photographing (projection) lens, 27° 34...Part of aperture, 27a, 34a...Rail surface, 28...Shutter curtain, 33...Shutter. Atsushi 3 Figure fmi"h 'b, 1

Claims (1)

[Claims] 1. In a projection device in which a projection unit having a slide film holder and its illumination system is made removable by replacing the camera back cover unit, the film support part has a film pressure plate made of a transparent material for fixing the film. A projection device characterized by: