JPH03146935A - Projecting device - Google Patents

Abstract

PURPOSE:To allow a camera used for photographing hitherto to function as a projecting device and to obtain a compact high-performance projecting device whose cost is low by making a unit having a slide film holding part and its illumination system attachable/detachable to the back cover unit of a camera having an automatic focusing function. CONSTITUTION:In the case of mounting the projection unit 18 to the camera 21, a pattern is projected on a screen, which is not illustrated, by an auxiliary light projecting device 29 and the reflected light is made to pass through a projection lens 22 and conducted to a focus detecting device 25 by a sub mirror 24. Focusing is performed based on the detected result at which time, a film F is positioned a specified amount lower than a position at the time of using as the camera, so that the focusing position is corrected. Thus, a distance from the rail surface 27a of the camera 21 to the film F is guaranteed, the film F side is irradiated with the light of an electric lamp 12 by a reflection mirror 11 in a projecting state, and infrared component is removed by an infrared cut filter 13. The flatness of the film F is secured by pressing plate 16 and a positioning plate 17.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a projection device that can be attached to and detached 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 the projection device of this scale.The light from the light source bulb 2 is efficiently irradiated onto the 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 condenser lens 4 prevents the light from spreading and efficiently irradiates the slide film F.The slide film F is held by its mount 5a and projected. By supporting the mount portion 5a, the device can support the slide film E at a predetermined position.

The light transmitted through the slide film F forms an image of the slide film F on a screen by the projection lens 6.

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 curl as shown in the solid line as shown in Fig. 8, and if it is projected onto a screen in this state, the screen will be distorted. The focus position differs between the periphery and the center, making it difficult to focus the entire screen, so this heat is released outside and the projection device & In order to prevent the projector from getting too hot, a cooling fan is used to blow outside air into the projector, or the high-temperature internal air is exhausted to cool the projector.

<Problems to be Solved by the Invention> However, the conventional slide projector described above is economically disadvantageous because the user must own both the camera for photographing and the projection device.

SUMMARY OF THE INVENTION In view of the problems of the prior art described above, it is an object of the present invention to provide an inexpensive projection device that can utilize a camera having an autofocus WJ function for photographing as a projection device.

<Means for Solving the Problems> In order to achieve the above object, the projection device of the present invention combines a projection unit having a slide film support and its illumination system with a back cover unit of a camera having an automatic focus adjustment function. It can be replaced and made detachable.

<Function> In the projection device configured as described above, the camera for photographing can be easily used as a projection device by replacing the back cover of the camera with the projection device and attaching it.

<Example> Hereinafter, a first example of the present invention will be described based on FIGS. 1 to 3.

1 and 2 are schematic cross-sectional views of a single-lens reflex camera having an automatic focus adjustment function, with a projection unit attached instead of a back cover unit (not shown).
The figure shows the adjustment state when the projection unit is attached, and FIG. 2 shows the projection state.

In the figure, reflecting mirrors 11. Light bulb for light source 12. Infrared cut filter 13
．． The condensing lens 14 made of a Fresnel lens, the film pressing plate 16 and the film positioning plate 17 made of a transparent material such as glass or acrylic paulownia are each loaded with zero spring force (thus, the fixed slide film F is A projection unit 18 that is removed from the held slide mount 15 is attached to the single-lens reflex camera 21 in exchange for a back cover unit (not shown).

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 submirror 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, at the top, there is a pentaprism 2 opposite the main prism 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 portion 27 having a diameter, and an auxiliary light projecting device 29 for distance measurement is disposed above the photographing lens 22 on the front side.

In this embodiment with the above configuration, the camera 2 shown in FIG.
When the projection unit 18 is attached to the projector 1, first, the auxiliary light projector 29 projects a pattern onto a screen (not shown), and the reflected light passes through the photographic lens 22 and is sent to the focus detection device 25 by the submirror 24. be guided. Then, based on the focus detection result, the lens is driven and the focus is adjusted, but since the film F is at a position lowered by a predetermined amount than when it is used as a camera, the focus position is corrected by this amount. There is a need. At this point, the light from the bulb 12, which is the light source of the projection device, is blocked by the shutter curtain 28 to prevent the focus detection device @25 from malfunctioning due to the light from the bulb 12. Furthermore, since the slide film F is fixed by the film pressure plate 16 and the film positioning plate 17, the distance from the rail surface 27a of the camera 21 to the slide film is guaranteed, and the accuracy of automatic focus adjustment (flange back) is also guaranteed. Ru.

Next, FIG. 2 shows the projection state, in which the light from the bulb 12 is efficiently irradiated onto the slide film F side by the reflecting mirror 11, the infrared component is removed by the infrared cut filter 3, and then the light from the light bulb 12 is filtered by the condenser lens 14. Light is guided to slide film F. Here, since the condenser lens 14 uses a Fresnel lens, the projection apparatus is miniaturized, but lenses other than the 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-barrel 24 are also rotated and retreated from the optical path.

Then, an image of the slide film F fixed by the film pressure plate 16 and the film positioning plate 17 is photographed (projected) and projected onto the screen by the lens 22.The infrared cut filter 13 also requires a large amount of light from the light source bulb 12. For example, the influence of the infrared component on the film and other parts can be reduced and can be omitted, and furthermore, the fan for cooling the projection device 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.
Since the flatness is maintained by this, it is possible to prevent the problems caused by the force of the slide film shown in FIG. 8.

Furthermore, since the distance δ from the rail surface 27a of the camera 21 to the slide film F does not change, once the focus is 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 adjusting the focus, it is only necessary to adjust the focus to a position corrected by this distance δ, so that automatic focus adjustment can be easily and at low cost.

Furthermore, by increasing the refractive index of the film positioning plate 17, 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. Therefore, it is particularly effective in cases where the distance from the projection lens 22 to the screen is large. Since the aperture part 27 of the camera 21 is covered by the film positioning plate 17, it is possible to prevent the shutter curtain 28 from being accidentally damaged and dirt from entering.

Furthermore, if the aperture part 27 of the camera 21 and the screen of the slide film F are largely misaligned, the screen will be 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. Since 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 symbol, and the difference b will be explained.

In this embodiment, a photographing lens 32 on the front side is used as the camera 31.
has a built-in shutter 33, and a part of the aperture 34 on the rear side.
A projection unit 18 is replaced and installed in place of the back cover unit of an autofocus camera that has a rail surface 34a formed on the front side and further includes 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 was designed to do so.

The configuration of the projection unit 18 is the same as that of the first embodiment described above.

In this embodiment with the above configuration, focus adjustment is performed by projecting infrared light from the light projecting unit 35 onto the screen, receiving the reflected light by the light receiving unit 36, and detecting the distance to the screen. 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.

Then, the projection of the image on the slide film is carried out as described above in the first step.
As in the embodiment, the infrared component of the light from the light bulb 12 is removed by the infrared cut filter 13, and the slide film F is irradiated by the condensing lens 14, and the image of the film is focused on the screen by the photographing lens 32. image.

Further, in this embodiment, the film positioning plate 17 does not go deep inside the aperture side 34 of the camera 31, but by making it go into the vicinity of the photographing lens 32, the film surface and the rail surface 34a are optically connected. Since it becomes possible to match the values, 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 dirt and foreign objects entering the photographic lens 32 (aperture side), and can also guarantee the flatness of the film, guarantee flange back, and prevent misalignment of the film screen and aperture. is also possible.

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

0 In this embodiment, the back cover of a single-lens reflex camera 21 that has the same automatic focus adjustment function as in the first embodiment is used as a projection unit 18a for a sleeve-shaped slide film Fa in which the slide film is not fixed to a mount. When installed in place of the unit, the slide film Fa 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. The other configurations are the same as those of the first embodiment described above.

The movement of this embodiment with the above configuration is similar to that of the first embodiment, but since the slide film F'a is directly pressed and fixed to the rail surface 27a of the camera 21 by the film pressure plate 16, it is normally All you have to do is adjust the focus in the same way as when taking a decoy image. Further, at this time, it is desirable that the shutter 28 be in a closed state in order to prevent harmful light from entering the focus detection, as in the first embodiment, but this is not necessary if the light bulb 12 is not emitting light. do not have.

In this embodiment, since the film positioning plate is omitted, the structure can be simplified, and the light from the film positioning plate does not fall.Furthermore, the film feed i4M of the camera 21 allows the slide film to be moved. The film transport method a is also possible, and there is no need to provide a special film transport 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.

This embodiment is similar to the third embodiment described above (an unmounted slide film, that is, the slide film Fa is projected onto the back cover of the Orcus camera 31 similar to the second embodiment) using the projection unit 18a. This is installed in place of the unit.Other configurations and operations are the same as those of the second embodiment.

In this embodiment as well, since the slide film Fa is directly pressed and fixed to the rail surface 348 of the camera 31 by the film pressure plate 16, focus adjustment can be performed in the same way as in normal photographing.

During projection, the light beam from the light bulb 12 that has passed through the slide film a is projected onto the screen by the projection lens 32.

<Effects of the Invention> As explained above, the present invention allows the camera, which was previously used for image reduction, to become a projection device by attaching the projection unit to the camera instead of the back cover unit, thereby reducing costs for the user. It can be made into an inexpensive, compact, and high-performance projection device.

Further, there is an advantage that the focus adjustment of the projection device can be performed using the automatic focus adjustment function of the camera as is.

[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. FIG. 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, and FIG. 6 is a schematic cross-sectional view of a fourth embodiment of the present invention. FIG. 7 is a schematic diagram of a conventional projection apparatus, and FIG. 8 is an explanatory diagram of a curled state of a film during projection in a conventional projection apparatus. 12...Light bulb, 13...Outside door cut filter, 14
...Condensing lens, 15...Slide mount, F.
... Slide film, Fa... Sleeve-shaped slide film, 16... Film pressure plate, 17... Film positioning plate, 18.188... Projection unit, 2
1゜31...Camera, 22.32...Tane's shadow (projection)
Lens, 27.34... Part of aperture, 27a, 3
4a...Rail surface, 28...Shutter curtain, 33...
·Shutter. Dance figure; figure 8

Claims (1)

[Claims] 1. A projection device characterized in that a projection unit having a slide film holder and its illumination system is made detachable by replacing it with a camera back cover unit having an automatic focus adjustment function.