JPS58132221A - Focusing screen provided with display part - Google Patents

Abstract

PURPOSE:To obtain a focusing screen where characters are seen correctly with single lines, by giving a light diffusing structure to a display part, which is formed to a recessed part or a projecting part, of the focusing screen where this display part is provided on the outside face directly. CONSTITUTION:A micromat 2 and a split image prism 3 for detecting the focus are provided on one face of a focusing screen 1. A recessed part 5 having a semicircular section is formed in the part where the micromat 2 is not formed, namely a focal plane 4 of the focusing screen 1, and the surface of this part 5 is a light diffusing face 5a. In this case, a light B2 incident to the lowest part of the recessed part 5 and a light B1 incident around it are reflected and diffused on the light diffusing face 5a as shown by B'1 and B'2 and are hardly transmitted through this part, and the recessed part 5 becomes black uniformly throughout its overall width W. That is, since the light B2 incident to the center part is not transmitted through and does not go straight, a double line is not generated, and one uniformly back line having the width W is seen.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bias hole focus 1iK on the outer surface of the display with a recess or a convex S.

In conventional focusing plates of this type, characters,
There are known display parts with numbers, lines, etc. engraved on them, and display parts with characters, numbers, -, etc. carved on inverted V-shaped protrusions. In such shallow water areas, the bottom corners of the 7-shaped groove tend to be rounded, and the tops of the inverted V-shaped protrusions sK are rounded. For example, when a focusing plate KV-shaped shank is engraved using a cutting machine, n is caused by wear of the cutting edge of the cutting tool.
It's a shame that I have to pay attention to the cutting edge of my part-time job at all times. On the other hand, when molding a focusing plate made of plastic ivy, when a 7-shaped groove is provided on the molded product by providing a 1lIK-1iv-shaped protrusion, the heat capacity of the tip of the protrusion of the mold is small. Therefore, the other parts 19 temperature decreases quickly and plastic is not sufficiently supplied.
When V*S is provided on the molded product to provide an inverted V-shaped protrusion, the pressure applied during molding will not reach every detail. Due to these reasons, how can Venus itself be placed and positive?
However, in molded products, the corners of the valleys of the 7-shaped grooves and the tops of the inverted V-shaped protrusions are often not formed accurately.

Light is transmitted through this square area without being reflected, and letters, numbers, lines, etc. are displayed as two black lines, making them difficult to see. A for the above drawbacks
Explain to the body.

Figures 111 (a) to (d) are mw v* outside the conventional focusing plate.
Island 1 (&), which shows a cross-sectional view when the display part is provided with a s or inverted V-shaped protrusion, shows the preferable case of V-shaped groove A, since the corner part at the bottom of the valley is not rounded. All incident rays B1 over the width WK of the V-groove A are reflected n and not transmitted; of course, the incident rays B1 to the bottom part of the valley of the V-groove A are also reflected, so that e.g. If is negative, it becomes a single black line with line width W.

Fig. 1(b) shows a case where the corner of the bottom of the valley of the V-shaped groove A is not accurate and, for example, the roundness is too high. lB
Since t is not reflected and advances to K[, if the display is 1, then lI
There will be two black lines, llIwl and the bird.

Summary 1 (C) shows the case of a preferable inverted V-shaped protrusion C,
Since the incident light #- on the top is also reflected, m1 diagram (a)
As in the case of 1fLt'! is displayed as a line. , 41 becomes a single black line with a width W.

In Figure m1 (d), the top S of the inverted V-shaped protrusion C is not accurate;
For example, if it is rounded, the incident light II Bt to the top is not reflected and proceeds to KIN, Figure s1 (b
), if the display is a line, it will be two black lines with a line width W1 and a crane.

In either case, there are such drawbacks, so conventionally, when providing a display section adjacent to the focus plate, it was necessary to put paint into the V-shaped groove or evaporate it onto the smooth surface of the focus plate. Instead of providing a contact display section, a crude method was used, such as printing a desired display on a film and sandwiching the film between a reticle and a mask. However, either method increases the number of man-hours and parts, and cannot be said to be a preferable method.

A specific example of actual NI in which the above-mentioned conventional method is adopted will be explained based on Figure 3 (&) of an optical viewfinder of a television camera. The viewfinder is composed of a focusing plate 1, a film 1, and a mask 1s. A micro mat 2 and a split image prism 3 are formed on the focusing plate 1, and a positioning projection 6 is provided in a protruding manner. On the film IK, transparent display characters Tab and opaque aperture scale numbers 1b are written, and a positioning groove 7@ and a window 1d of the 7 pertier window are formed. The mask 8 is made of an opaque material, and has a display character display window 11as, an aperture 9 scale illumination window 8b, and a positioning #1.
11@ and an aperture window 8d are formed.

In this case, the viewfinder consists of three members (1, 7
Since the number of parts is increased by 1, the number of man-hours increases by 1, and the relative position between the reticle 1 and the film 7 and between the film 7 and the mask 8 has to be changed. Positioning is the membership fee. Furthermore, the printing on the film 7 must be finished with considerable precision because the characters are magnified using an eyepiece.

The present invention aims to eliminate all of the above-mentioned drawbacks. In other words, even if the stacking density at the top of the convex part or the bottom of the concave part is less than SZ, almost no light will pass through this part, regardless of the quality of the molding technology. The purpose is to provide a focusing plate that allows characters, etc. to appear correctly -m.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an explanation will be given based on drawings showing actual examples of the present invention. In Figure 2 (a), a micromat 2 and a split image prism 3 are provided on one surface of a focusing plate 1 for detecting focus. Micromat 2 of focus plate 1
is formed, and the cross section is half F for 1vhs, that is, the focal point 1m4.
A q-shaped concave F9rs is formed 1op, and its surface serves as a light diffusion 1f151.

In this case, the light B incident on the bottom of the concave s5 (the center 1tN)
, and the light B incident on its surroundings.

As shown, the light is reflected and diffused, and almost no light passes through this portion, so that the entire width W of the concave F9rs becomes uniformly black. Rima 9, middle/Light B incident on L7s! Since the light does not pass through and go straight, there is no double IIIVc, but a single uniformly black line with a width W.

Fig. 142 (b) The Tomomi example shown in 4C is the same as the above example except that a semicircular cross-sectional convex s5' is formed in D instead of the recess S, and its surface becomes a light diffusing surface 5a/1. Since it is similar to the above, corresponding parts are shown with the same numbers and detailed explanations are omitted.

When the focusing plate 1 shown in Figure 2 (it) is molded from plastic, a gold fiK micromat 2 and a split image prism 8 are provided, and the ninth recess of the Kll support is etched into the gold jl. engrave. This is L convex
Light diffusing 1 isa is naturally formed on the so surface. If you make it in this way and mold the plastic with 9-kin sandals,
It is possible to produce IK2 in large quantities at low cost and with stable quality, with the focal point II having the convex display S shown in FIG.

Further, it is not necessary to provide a rounding process to form a light-diffusing surface next to the flr, which is convenient. Incidentally, a recess or a convex portion for display may be provided in the crest where the micro mat 2 and the split image prism 3 are provided.

Figure 3 (b) shows the implementation of the present invention as applied to a viewfinder of a television camera. A reticle 1 is formed with a micromat 2 and a split image prism 8, and according to the invention, a concave or convex s of a light diffusing structure is formed.
9 is formed so that the aperture scale is displayed as 1 in n%cn [
There are 71. , the casing, and the film sK are formed with U-shaped, V-shaped, and W-shaped display windows 8a, as well as positioning patterns 8e and 7 pertier windows 8d. The viewfinder is 1 pf relative to the focal point IEI and film 6.

Due to this simple structure, the conventional film can be saved, the number of S parts is reduced, and the number of man-hours is reduced. Sometimes films are difficult to handle during the assembly process, and being able to eliminate this process is a huge advantage.

In addition, the present invention is applicable to the above actual J1m? However, the concave portion or the convex portion may be V-shaped, and only the bottom or top portion of the valley may be a light diffusing surface.

As mentioned above, the favorite is Q11! If the concave or convex part of the light diffusing structure is attached to the outside of the focusing plate, it can be indicated by a single uniformly black Ill regardless of the quality of the molding technique using the mold. .

[Brief explanation of the drawing]

Ill I WJ (a) to (d) are cross-sectional views of a reticle for explaining the problems of the prior art, Figure 42 (aJ is a cross-sectional view showing one example of a part of the present invention, 142
Figure (b) is a sectional view showing another practical example of the present invention, Figure 3 (
Fig. 3(b) shows a part of the optical viewfinder of a TV camera using the focusing plate according to the present invention. ! This is a J1 diagram. (Explanation of the symbols of the main 11 parts) 1... Focal plane... Focal plane 5... Concavity 5'... Protrusion 9... Concave or convex part Atsushi 1, Atsushi 2 ( b)

Claims (1)

[Claims] A focal point f in which a concave or convex display section is provided directly on the outer surface.
In EK, a focal point li equipped with a display section, characterized in that the display section has a light diffusing structure.