JPS6141083Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a single-lens reflex camera, particularly to a circuit structure for a single-lens reflex camera.

In recent years, cameras have been required to be smaller and lighter, while it is also desired to automatically perform various photographing modes, and it is necessary to incorporate extremely sophisticated electric circuits into the cameras. However, in cameras, the placement position of the circuit becomes an issue due to space issues. For this reason, it is conceivable to apply a method of arranging a flexible printed board inside the camera body and arranging a circuit on the printed board, as shown in US Pat. No. 3,670,639, for example.
When applied to an eye reflex camera, there is a drawback that positioning of the light receiving element requires a lot of effort.

That is, in a single-lens reflex camera, since it is necessary to photometer the subject light, the light-receiving element must be positioned on the exit surface of the pentablism, which requires a lot of effort.

The present invention was developed in view of the above-mentioned matters, and its purpose is to facilitate the positioning of the light-receiving element to face the exit surface of the pentagonal roof prism. The circuit board is constituted by a flexible printed circuit board having a board part that is shaped almost the same as the surface, and an extension board part that is integrally formed with the board part, and the camera's electricity is installed on the surface of the board part. A circuit element is disposed, and a light receiving element is disposed on the back surface of the extension board part, and the board part is further disposed with the surface facing up along the roof-shaped surface of the pentagonal roof prism, and the extension board part and the board are disposed together. A printed circuit board structure structure in which a boundary between the pentagonal roof prism and the exit surface is located approximately at the boundary between the roof-shaped surface of the pentagonal roof prism and the exit surface, and the boundary is bent so that the light-receiving element faces the exit surface. It is an object of the present invention to provide a printed circuit board structure for a single-lens reflex camera in which the light receiving element can be easily positioned on the exit surface of the pentagonal roof prism by bending the boundary portion.

The present invention will be explained below with reference to the drawings. FIG. 1 is a developed plan view of a board used in an electric control circuit structure according to the present invention.

In the figure, reference numeral 1 denotes a flexible printed circuit board for wiring, which has a developed shape similar to, for example, each non-functional surface of a pentaprism. The black pattern portion 2 is an electrical conductor, and is a printed wiring portion formed by photoetching a thin metal film such as copper foil.

FIG. 2 is a perspective view showing an embodiment in which individual circuit elements are attached to the substrate of FIG. 1 and arranged along the roof surface of a pentaprism. In the figure, 1 is a flexible printed circuit board, 2 is an electric conductor, and 3 is a flexible printed circuit board.
IC, 4, 4', 4'' are variable resistors for adjustment, 5, 7
6 is a resistive element, 6 is a capacitor, 8 is a changeover switch, 9 is a pentaprism, and 10 is a light-receiving element arranged on an extension board part from the board part on which the above-mentioned resistive element etc. are arranged, and this element is shown in the figure. As shown in FIG. In the illustrated embodiment, the light receiving element 10 is placed in close contact with the rear surface (exit surface) of the pentaprism 9, and has a good TTL photometry function, and is placed adjacent to the IC 3, so it forms a high impedance circuit. Even in such a case, reliable operation can be achieved without causing instability of the circuit due to stray coupling or the like. The individual adjustment resistors 4, 4', 4'' and others are mounted in contact with the board 1, and the terminals of the various switches 8 can also be provided directly on the board, so the thickness of the circuit body can be made as small as possible, and the camera This means that the internal volume can be used effectively.

As described above, in the present invention, a flexible printed circuit board is provided which has a board part having almost the same shape as the roof-shaped surface of the pentagonal roof prism, and an integrated extension board part, and circuit elements are arranged on the surface of the board part. On the other hand, a light-receiving element is arranged on the back side of the extension board part, and the board part is arranged with the surface facing up along the roof-shaped surface of the pentagonal roof prism, and the boundary part between the above board part and the extension board part is placed on the pentagonal roof prism. With this configuration, the light-receiving element can be positioned on the emission surface very easily by bending the boundary, making it easier to position the light-receiving element. This has the effect of simplifying the process.

[Brief explanation of drawings]

FIG. 1 is a developed plan view showing an embodiment of a substrate used in the structure of the present invention, and FIG. 2 is a perspective view showing an embodiment of the circuit structure according to the present invention disposed in a camera. 1... Printed circuit board, 2... Electric conductor, 3...
IC, 4, 4', 4''...Adjustment variable resistor, 5,
7... Resistance element, 6... Capacitor, 8... Selector switch, 9... Pentagonal roof prism,
10... Light receiving element.

Claims (1)

[Scope of utility model registration request] The circuit board is constituted by a flexible printed circuit board having a board portion having a shape substantially the same as the roof-shaped surface of the pentagonal roof prism, and an extension board portion formed integrally with the board portion, and the board portion An electric circuit element of the camera is disposed on the surface of the extension board, and a light receiving element is disposed on the back surface of the extension board, and the board is disposed with the surface facing up along the roof-shaped surface of the pentagonal roof prism. The boundary portion between the extension substrate portion and the substrate portion is located approximately on the boundary side between the roof-shaped surface and the exit surface of the pentagonal roof prism, and the boundary portion is arranged such that the light receiving element of the extension substrate portion faces the exit surface. A printed circuit board structure for a single-lens reflex camera, characterized in that a portion of the printed circuit board is bent.