JPS6235078Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a viewfinder information display device for a single-lens reflex camera, and particularly to a viewfinder information display device for displaying viewfinder information using two types of illumination light: light from outside the camera and light from a light emitter placed inside the camera. This invention relates to improvements in structures for illuminating information bodies.

Methods of illuminating an information body for viewfinder information display located inside a camera with two illumination lights include, for example, guiding light from outside the camera to the information body via an optical system and guiding light from an illuminator located inside the camera to the information body via another auxiliary optical system. However, these methods generally have drawbacks such as requiring a large space inside the camera, which places restrictions on the design of the camera body, and making the structure of the auxiliary optical system complex and expensive.

The purpose of this invention is to provide a small and simple structure that can illuminate an information body for displaying viewfinder information using two types of illumination light: light from outside the camera and light from a light emitter placed inside the camera. Therefore, it is possible to provide a viewfinder information display device for a single-lens reflex camera that is not subject to restrictions on the design of the camera body, is easy to manufacture, and is inexpensive. In order to achieve this purpose, the finder information display device of the present invention directs external light received through a lighting window provided on the camera surface through a total reflection prism to an information body for displaying finder information placed inside the camera. At the same time, a light emitting body is disposed on the back side of the total reflection surface of the reflecting prism, and the light from the light emission body is transmitted through the total reflection surface and guided to the information body for illumination.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a schematic diagram of an embodiment of the invention.

Reference numeral 1 denotes a pentagonal roof prism, and the side surface of the bottom entrance surface is obliquely processed to have a transmitting surface 11. 2
is a triangular prism and has transmission surfaces 21 and 22 and a reflection surface 23 with a reflective film attached, and the transmission surface 22
is arranged to face the transmission surface 11 of the pentagonal roof prism 1 with a small distance therebetween. 3 is an information body such as a shutter scale, an aperture scale, and a meter pointer. 4 is a prism for guiding light from a lighting window (not shown) provided on the camera surface to the information carrier, and has an entrance side transmission surface 41, a reflection surface 42 using total reflection, and an exit side transmission surface 43. 5 is a light emitting body, and in the embodiment shown in this figure, a light emitting diode is used.

Illumination light K from outside the camera enters the prism 4 from the entrance side transmission surface 41, is then totally reflected at the reflection surface 42, exits this prism 4 from the exit side transmission surface 43, and enters the information carrier 3. be directed. The information light L from the information body 3 illuminated by the illumination light K enters the triangular prism 2 through the entrance surface 21 of the prism 2, and exits the transmission surface 22 through total reflection by the transmission surface 22 and reflection by the reflection surface 23. and is directed toward the transmission surface 11 of the pentagonal roof prism 1. The light enters the prism 1 from this surface, follows the same optical path as the photographing field light, and is displayed as display information I on the side of the photographing field F, as shown in FIG. On the other hand, the illumination light M from the light emitter 5 arranged inside the camera is reflected by the total reflection surface 42 of the prism 4.
The information 3 enters the prism 4, and then exits the prism 4 through the exit-side transmission surface 43.
The information body 3 is illuminated.

As described above, the finder information display device of the present invention guides illumination light from outside the camera to the information body using a prism that utilizes total reflection, and also places a light emitting body in a small space behind the total reflection surface of this prism. It has an extremely simple configuration that does not require a large space inside the camera and is not subject to camera design constraints, and also requires an auxiliary optical system to guide the illumination light from the light emitter to the information body. It has the advantage that it is easy to produce and inexpensive because it does not require any oxidation.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the optical arrangement of the finder display device of the present invention, and FIG. 2 is a diagram showing the viewfinder field of view of the finder display device of FIG. 1. In the figure, 1... pentaprism, 2, 4... prism, 5... light source, 3... information body, K... external light.

Claims (1)

[Scope of utility model registration request] A penta-roof prism 1 having a transparent surface 11 formed by obliquely cutting the corners of its bottom surface and a triangular prism 2 whose bottom surface has been subjected to a reflective treatment are arranged with a gap so that their slopes face the transparent surface, a light guide prism 4 having an incident surface for taking in outside light directed upward, an exit surface directed toward the pentagonal roof prism, and a slope for totally reflecting the incident light on the inner surface;
An information display body 3 and a light emitting diode 5 that illuminates the information display body from the outside of the light guide prism 4 through the slope are arranged between this light guide prism and the triangular prism, and external light and light emitted from the light emitting diode are disposed. A viewfinder information display device in which light from an information display body illuminated by the triangular prism is sequentially reflected from the slope and bottom surface of the triangular prism, and then enters the pentagonal roof prism through the transmission surface.