JPH02120727A - Display mark observation device - Google Patents

Abstract

PURPOSE:To make a display mark being an object easily visible by constituting the title device so that plural display marks in a finder are illuminated independently, respectively. CONSTITUTION:On a transparent plate 6 between a focusing screen 5 of a camera and a condenser lens 7, for instance, on a part in a photographing screen 21, three display marks 22 - 24 consisting of plural verty small prisms for showing a focus detecting range are formed. Also, illumination use light sources 12a - 12c of the marks 22 - 24 are placed on a production of a line for linking the center 0 of a concentric circle and about the center of the mark so that each mark can be illuminated independently. In such a way, only the display mark being an object can be illuminated efficiently, and only its reflected light can be observed by an eye point 10 through an eyepiece 9.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a display mark observation device suitable for photographic cameras, video cameras, etc., and mainly involves display marks on a finder image formed by an objective lens (taking lens). This invention relates to a display mark observing device in which the finder image and the display mark are observed at the same time by spatially overlapping them in a so-called superimposed manner.

(Prior Art) Conventionally, in viewfinder-based observation devices such as photo cameras and video cameras, various displays related to photography, such as shutter speed, aperture value, sidelight range, distance measurement range, etc., are displayed along with the finder image formed by the objective lens. The marks are displayed simultaneously and both are observed through the eyepiece. The display mark is made of, for example, a liquid crystal, and is arranged at the center or periphery of the photographic screen, and is illuminated by an illumination means and observed through an eyepiece.

Of the display marks, the distance measurement mark indicating the distance measurement range for automatic focus detection and the metering mark indicating average metering, center-weighted metering, etc. are displayed spatially overlapping with the viewfinder image in the center of the shooting screen. There are many cases.

Recently, various automatic focus detection devices have been proposed that perform focus detection in a plurality of areas within a photographic screen.

In this case, it becomes necessary to provide distance measurement marks at multiple positions within the field of view of the finder. Then, it becomes necessary to select only the target distance measurement mark from among these plurality of distance measurement marks and independently illuminate and display it.

However, finder systems such as cameras are generally small and housed in a narrow space, so it is very difficult to arrange multiple lighting means to independently illuminate only the target distance measurement mark, and in many cases There were problems such as other distance measurement marks being illuminated at the same time.

These problems also apply to photometric marks.

(Problems to be Solved by the Invention) When the present invention provides a plurality of display marks within the field of view of the finder, the display marks are composed of a plurality of minute prisms having a predetermined shape, and a predetermined display mark is selected from among the plurality of display marks. It is an object of the present invention to provide a display mark observation device suitable for a photographic camera, a video camera, etc., which can illuminate only the display mark with an illumination means and enable good observation of the display mark.

(Means for solving the problem) A plurality of display marks each formed by arranging a plurality of microscopic prisms in a concentric circle are provided on a part of a transparent flat plate, and the center of the concentric circle in which the plurality of microscopic prisms are arranged and the corresponding display mark are provided. An illumination means for illuminating the display mark is arranged on an extension line connecting approximately the centers of the marks, and the display mark illuminated by the illumination means is observed through an eyepiece.

(Embodiment) FIG. 1 is a schematic diagram of an optical system of an embodiment when the display mark observation device of the present invention is applied to a single-lens reflex camera.

In the figure, reference numeral 1 denotes a photographing lens which has an aperture 2 in its optical path. 3
is a rotating mirror with a semi-transparent surface 3a in part,
The imaging light beam L1 is divided into two, one light beam L2 is guided to the finder system, and the other light beam L3 is guided to the focus detection device 13. A sub-mirror 4 is fixed to the mirror 3 and guides the light beam L3 that has passed through the semi-transparent surface 3a of the mirror 3 to the focus detection device 13. Reference numeral 5 designates a focusing plate, the entrance surface 5a of which is a Fresnel lens, and the exit surface 5b of which is a matte surface.

Reference numeral 6 denotes a transparent flat plate, and as shown in FIG. 2, for example, three display marks 22 to 24 made of a plurality of minute prisms, which will be described later, are formed in a part of the photographing screen 21 to indicate a focus detection range. 7 is a condenser lens, 8 is a pentaprism, 9 is an eyepiece, 10 is an eye point for observation,
11 is a photosensitive surface. A light source 12 illuminates display marks 22 to 24 formed on the transparent flat plate 6, and includes illumination means 12a to 12c such as LEDs. 1
Reference numeral 5 denotes a light guide prism, which is composed of three light guide members 15a to 15c corresponding to the respective illumination means 12a to 12c, as shown in FIG. 2, for example.

In this embodiment, the light beam L5 from the light source 12 is transmitted through the light guide prism 1.
5 and enters the inside of the transparent flat plate 6 from the end surface thereof,
The light travels through the transparent flat plate 6 while being totally reflected between its surfaces, reaches the display marks 22 to 24, and illuminates the display marks.

A part of the light beam 16 that illuminates the display mark is reflected by one slope of the micro prism that constitutes the display mark,
The light of the finder system is emitted in the direction of l1iIllL4,
It is observed at an eyepoint 10 by a pentaprism 8 and an eyepiece 9.

In this embodiment, when the display light beam reflected and emitted from the minute prism constituting the display mark (23) passes through the eyepiece lens 9, the light beams La and Lb passing through the edge of the finder aperture 16 fall within the angle α. It is set so that it spreads uniformly.

Next, the shapes of the display marks (22 to 24) of this embodiment will be explained.

As shown in FIG. 2, each of the display marks 22 to 24 is composed of an aggregate of a plurality of micro prisms, and each micro prism is arranged concentrically and arcuately around point 0. . One display mark 22 is composed of two left and right display sections 22a and 22b. The same applies to the other display marks 23 and 24.

FIG. 3 is a cross-sectional view of a part of the prism-shaped display mark of this embodiment, and FIG. 4 is a perspective view of display marks 22 to 24 made of the prism. As shown in the figure, the minute prism has an arcuate triangular shape.

In FIG. 3, 17 is a colorless and transparent acrylic material, and 18 is a fine triangular prism body. A reflective film is applied to the surface of the prism body in the region 21a where incident light is reflected for display purposes.

This forms a display section as a prism reflecting section. Further, the other region 21b is left untreated.

The acrylic materials 17 and 18 are made of materials with substantially the same refractive index, and the adhesive 1 has substantially the same refractive index as the acrylic materials 17 and 18.
9 glues both sides together. As a result, only the area 21a coated with the reflective film for the display part has a reflective effect due to the prism, and the incident light L5 is reflected in a predetermined direction, so that the luminous flux L for display is generated.
4, the light is guided to the eyepiece (not shown) side.

As shown in FIG. 5, the display marks 51 to 53 are formed on a metal plate by simply arranging a plurality of minute prisms in parallel rather than in concentric circles, and the display marks 51 to 53 are formed by light sources 51a and 52, respectively.
Assume that the configuration is such that the light is illuminated by the lights 53a and 53a. For example, assume that the light source 52a is turned on to illuminate the display mark 52. Then, as shown in FIG. 6, the luminous flux L62 incident on the prism of the target display mark 52 is reflected by the display mark 52 and enters an eyepiece (not shown), so that the display mark 52 is observed.

At the same time, the front light beam from the light source 52a also enters the prisms of non-target display marks 51 and 53 that are close to the display mark 52. At this time, display mark 51.53
The incident light beams L61°L63 are reflected in the same direction as the light beam L62, and a portion thereof enters an observation eyepiece (not shown).

For this reason, the display marks 51 and 53, which are not the object, are also displayed within the viewfinder field of view together with the display mark 52, which is the object, resulting in an erroneous display, and this is undesirable as it is distracting to the observation equipment.

On the other hand, in this embodiment, as shown in FIG. 2, the light sources 12a to 12c for illuminating the display marks 22 to 24 are arranged on an extension of a line connecting the center O of the concentric circle and the approximate center of the display mark. ing. Each of the display marks 22 to 24 is independently illuminated by the light sources 12a, 12b, and 12c. As a result, only the target display mark is efficiently illuminated, and even if the illumination light enters another display mark, the reflected light from the display mark will not enter the eyepiece, thereby achieving the target display. Only the marks are observed.

FIG. 4 is an explanatory diagram of the state of reflection of the luminous flux from the minute prism forming the display mark at this time.

The figure shows the display mark 2 when the light source 12c is turned on in FIG.
3 is shown.

As shown in the figure, when the light source 12c is turned on, since the target display mark 23 has prism bodies arranged concentrically, the luminous flux L42 reflected by the display mark 23 enters the eyepiece of the finder system. However, the luminous flux L41. which entered the other display marks 22.24. L43 is largely reflected obliquely on the surface of the arc-shaped prism, so it does not enter the eyepiece. Therefore, only the target display mark 23 is observed through the eyepiece.

As described above, in this embodiment, by arranging the display mark and the light source for illuminating the display mark as described above, only the target display mark is observed together with the finder image within the viewfinder field of view.

In this embodiment, the prism constituting the display mark is not limited to a triangular shape, but may have any shape as long as it can reflect incident light in a predetermined direction.

(Effects of the Invention) According to the present invention, a plurality of display marks to be displayed within the field of view of a finder are each configured by a plurality of micro prisms arranged concentrically, and the display marks are emitted from a light source arranged in a predetermined direction. By independently illuminating with a luminous flux, it is possible to achieve a display mark observation device with a simple configuration that can select and display only the target display mark.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of the optical system when the present invention is applied to a single-lens reflex camera, Figure 2 is an explanatory diagram of a portion of Figure 1, and Figures 3 and 4 form the display marks in Figure 1. Figures 5 and 6 are schematic diagrams of conventional display marks and their main parts. In the figure, 1 is a photographing lens, 3 is a rotary mirror 5 is a focusing plate, and 6 is a Transparent flat plate, 7 a condenser lens, 8 a pentaprism, 9 an eyepiece lens, 22.
23.24 is a display mark, 12.12a. 12b and 12c are light sources, and 15, 15a, 15b. 15c is a light guide member, and 11 is a photosensitive surface.

Claims (1)

[Claims] (1) A plurality of display marks composed of a plurality of micro prisms arranged in concentric circles are provided on a part of a transparent flat plate, and an extension connecting the center of the concentric circle in which the plurality of micro prisms are arranged and the approximate center of the display mark A display mark observing device characterized in that an illumination means for illuminating the display mark is arranged on a line, and the display mark illuminated by the illumination means is observed through an eyepiece.