JPH0442824Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a shielding cover for covering an active distance measuring device using infrared light.

[Conventional technology]

The active type distance measuring device used in recent cameras consists of a light source such as a light emitting diode that emits infrared light, a light projecting lens placed in front of the light source, and a light emitting unit that emits infrared light. The light receiving unit includes a light receiving body such as a position sensor that photoelectrically detects the incident position, and a light receiving lens disposed in front of the light receiving body. When the light emitting part and the light receiving part are arranged with a certain base line length apart, and the respective optical axes of the light emitting lens and the light receiving lens are made parallel to the optical axis of the photographing lens, the light emitting part and the light receiving part are placed behind the light receiving lens. Since reflected light from the subject is focused on the placed photoreceptor at a position corresponding to the subject distance, it is possible to determine the subject distance.

Incidentally, each of the light source and the photoreceptor is arranged on the front surface of the camera body so as to face the subject, and a dustproof cover is placed over the front surface of the camera body. This dustproof cover has a transparent window at least in the portion facing the light projecting lens and the light receiving lens so as not to block the light flux from the light source or the light flux entering the light receiving body.

[Problem that the invention attempts to solve]

The light source and photoreceptor described above are connected to a circuit unit for operating them via an electric cord, a printed board, or the like. Therefore, even if the part facing the light emitting and receiving lenses is covered with a cover that has a transparent window as in the past, if the line of sight is slightly tilted, the internal wiring can be seen through the transparent window. It is visible and the appearance is very unsightly.

The present invention was developed to solve these drawbacks of the conventional technology, and it has been developed to improve the light emitting part and the light receiving part, which make up an active type distance measuring device that uses infrared light, as well as the wiring part of these parts. To provide a shielding cover for a distance measuring device that completely shields the device and does not affect the operation of the distance measuring device at all.

[Means for solving problems]

In order to achieve the above object, the present invention uses a cover with spectral characteristics that transmits infrared light used for distance measurement and blocks visible light. This completely covers the light receiving section and the light receiving section.

An embodiment of the present invention will be described below with reference to the drawings.

〔Example〕

In FIG. 1 showing an embodiment of the present invention, a lens cover 2 is provided on the front surface of a camera body 1 so as to be slidable. When the lens cover 2 is opened as shown, the photographing lens 3, the viewfinder 4,
Further, the light projecting section 5 and the light receiving section 6 of the distance measuring device are exposed.

As is well known, the light projecting section 5 includes a light projecting lens and a light source, and emits an infrared light beam toward the subject along an optical axis parallel to the optical axis of the photographic lens 3. A light receiving section 6 is arranged directly below the light projecting section 5 with a certain base line length apart. The light-receiving unit 6 also has a light-receiving lens 7 and a light-receiving body 8 so that its optical axis is parallel to the optical axis of the photographing lens 3.
(See Figure 2). Then, the light projecting section 5
The spot light irradiated toward the subject is reflected by the surface of the subject, and a part of this reflected light flux is focused on the photoreceptor 8 via the light-receiving lens 7. As in the illustrated embodiment, when the light projecting section 5 and the light receiving section 6 are arranged vertically, the spot light reflected from the subject is incident on the lower side of the light receiving body 8 as the distance to the subject becomes shorter. However, as the distance becomes infinite, the light comes to be incident on the upper side of the photoreceptor 8. The photoreceptor 8 detects the position of the incident light as described above.
Output as an electrical signal.

As shown in FIG. 2, the photoreceptor 8 is connected to a processing circuit 11 via a printed board 10. As shown in FIG. An electrical signal regarding the incident position of the spot light onto the photoreceptor 8 is input to the processing circuit 11. The processing circuit 11 performs calculations based on the electrical signal and outputs a ranging signal. The distance measurement signal obtained in this way is used as a control input for the lens drive mechanism that controls the extension of the photographic lens 3, so the extension position of the photographic lens is automatically adjusted according to the subject distance based on the distance measurement signal. will be set to .

A shielding cover 15 is attached to the front surface of the light projecting section 5 and the light receiving section 6. This shielding cover 1
5 is manufactured by molding an acrylic resin plate mixed with black pigment, for example, and its spectral transmission characteristics are as shown in FIG. In other words, more than 95% of the infrared light around 900 nm that is irradiated from the light projector 5 to the subject is transmitted, and the transmission of light in the visible light range (approximately 400 to 650 nm) is reduced to 5% or less. Keep it to.

Shielding cover 15 with such spectral transmission characteristics
is placed in front of the light emitter 5 and the light receiver 6, the light emitter 5, the light receiver 6, and the printed board 1
Wiring parts such as 0 are completely hidden from the front of the camera, and the appearance of the front of the camera can be organized very neatly. Also, unlike conventional autofocus cameras, both the light emitter 5 and light receiver 6 for distance measurement are hidden, making it possible to create innovative designs for autofocus cameras. .

Further, when the lens cover 2 is closed, the front surfaces of the photographing lens 3 and the viewfinder 4 are covered, and these can be protected when not in use. At this time, the end of the lens cover 2 is adjacent to the end of the shielding cover 15, so that the lens cover 2 and the shielding cover 15 have a continuous appearance without unevenness, and the portability is improved.

On the other hand, most of the infrared light from the light emitter 5 used for distance measurement and the infrared light incident on the light receiver 6 are transmitted, so there is no effect on the distance measurement function. do not have. Moreover, since there is no need to provide a transparent window in a part of the shielding cover 15 to expose the front surface of the light projecting section 5 and the light receiving section 6, unlike the conventional shielding cover 15, the manufacturing of the shielding cover 15 is also simplified. For this purpose, it is preferable that the viewfinder 4 is not disposed between the light projecting section 5 and the light receiving section 6 as in the above embodiment. In addition, if the area does not block the light beam emitted from the light projector 5 or the light beam incident on the light receiver 6, accent lines 16, marks 17, etc. that have a design effect may be printed on the shielding cover 15. You can also do that. In addition, in carrying out the present invention, the form of the lens cover 2 may be changed or omitted, and the arrangement of the light emitting section 5 and the light receiving section 6, that is, the direction of the base line length may be changed to the horizontal direction. good.

[Effect of idea]

As described above, the shielding cover for a rangefinder of the present invention transmits infrared light used for rangefinding, but blocks most of the visible light, so it does not interfere with the rangefinder function in any way. It becomes possible to completely hide not only the wiring part attached to the distance measuring device but also the light emitting part and the light receiving part. Therefore, compared to conventional autofocus cameras, the exterior design can be very streamlined.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing one embodiment of the present invention. FIG. 2 is a sectional view of essential parts of an embodiment of the present invention. FIG. 3 is a spectral characteristic diagram of the shielding cover used in the present invention. 1...Camera body, 2...Lens cover, 3
...Photographing lens, 4...Finder, 5...Light emitter, 6...Light receiving section, 7...Light receiving lens, 8...Photoreceptor, 10...Printed board, 11...Processing circuit,
15... Shielding cover.

Claims (1)

[Claims for Utility Model Registration] (1) A light emitter that emits infrared light toward a subject for distance measurement, and a light receiver that receives a portion of the infrared light reflected from the subject. A camera whose front surface is protected by a cover, characterized in that the cover is provided at a position away from the viewfinder optical path and is a one-piece shielding cover that has spectral characteristics that transmit infrared light and block visible light. A camera with a shielding cover for distance measuring equipment. (2) The camera with a shielding cover for a range finder according to claim 1, wherein the shielding cover is an acrylic plate mixed with a black pigment. (3) The light projecting section and the light receiving section are vertically arranged next to the photographic lens, and the front surfaces thereof are covered by the vertically elongated shielding cover, and the front surface of the photographic lens is provided with an opening/closing section that can be slid horizontally. A camera with a shielding cover for a distance measuring device according to claim 1, wherein a cover is provided, and the opening/closing cover is adjacent to the shielding cover when closed.