JP2001075149A - Display device within finder screen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device within finder screen capable of realizing the miniaturization of a single lens reflex camera and appropriate display within a finder screen. SOLUTION: A microprism constituting a range-finding point of an AF (autofocusing) frame is formed on the finder image side surface of an SI (superimposing) screen 2. At least one surface of the microprism is constituted of a cylindrical surface. A light source unit 6 emitting illuminating light and a prism lens for projecting light 8 guiding the illuminating light to the microprism are arranged on the outside of a finder optical path. Superimposing display is performed by reflected light from the illuminated microprism.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a finder screen display device, and more particularly, to a finder screen display for superimposing and displaying various information necessary for photographing in a finder screen of a single-lens reflex camera. It concerns the device.

[0002]

2. Description of the Related Art A finder of a general camera is provided with a function of displaying various information necessary for photographing in a finder field of view. Information necessary for shooting includes exposure-related data (shutter speed, aperture value, exposure compensation value, etc.), shooting area (view frame display), ranging area (AF frame display), metering area (metering frame display), focus The detection result (in-focus / out-of-focus, front / back focus), focus adjustment direction, flash light-related data, and the like are included. Among these pieces of information, the distance measurement area and the photometry area are displayed in a finder screen on which a subject image is displayed.

In a single-lens reflex camera having a multi-point AF (autofocus) function, one of a plurality of ranging points in a ranging area is automatically selected by the camera or manually selected by a user. Further, it is necessary to further display which distance measuring point is currently selected. If the selected ranging point is not displayed, AF may be performed on an object other than the main subject without the user noticing. As one method for displaying the focus detection points, a method is known in which a selected focus detection point is superimposed and displayed in a finder screen by an LCD (liquid crystal display). However, in this method, since the AF points are displayed by dark display of the AF frame, there is a problem that the visibility decreases when the finder screen becomes dark (for example, when the subject has low brightness).

According to the illumination display system proposed in Japanese Patent Application Laid-Open No. 8-43913, the above problem does not occur. A finder configuration employing this method will be described with reference to FIG. According to this finder configuration, the light emitted from the photographing lens (not shown) is reflected by the movable mirror (10), and then is positioned at an equivalent position of the film (F).
(11) Image is formed on the top. As a result, a finder image (subject image) is formed on the reticle (11), and a finder light beam emitted from the reticle (11) forms a finder screen. The finder light beam emitted from the reticle (11) is SI (superim
pose) After passing through the screen (13) and the condenser lens (15), the light enters the pentaprism (12) from the surface (12b). The pentaprism (12) is an inversion prism that inverts the finder image on the focusing screen (11) to make an erect image.
The finder luminous flux incident on the pentaprism (12) and reflected on its three reflecting surfaces is combined with the eyepiece optical system (14) and the protective glass.
It passes through (16) and reaches the pupil (not shown).

On the other hand, above the pentaprism (12), an LED (light emitting diode) package (18) as a light source for illumination, a light projecting lens (19) having a special shape, and the like are arranged. The illumination light emitted from the LED package (18) is transmitted to the pentaprism (12) by the projection lens (19).
Incident on the surface (12a). This surface (12a) is a pentaprism
This is a surface surrounded by the three reflecting surfaces of (12) and is not used as a surface that performs an optical function for image inversion. The light enters the pentaprism (12) from the surface (12a)
The illumination light emitted from b) passes through the condenser lens (15) and then enters the SI screen (13). On the side of the viewfinder image of the SI screen (13),
A microprism (13a) composed of an F frame is formed (FIG. 8). Part of the illumination light incident on the SI screen (13) is totally reflected by the micro prism (13a) to become a display light flux as shown in FIG. 8, and merges with the finder light flux. As a result, the ranging point display including the AF frame is introduced as a superimposed display in the finder screen.

The size of the microprism (13a) is smaller than the diameter (= Da) of the light projecting lens (19) and the optical path length (= Db) from the light projecting lens (19) to the microprism (13a). Since it is sufficiently small, the equation: θ2 = θ3 = arctan (Da / Db) holds in FIG. Each principal ray L represented by a broken line and a solid line
2, L3 {that is, light rays passing through the center of the light projecting lens (19)} are substantially parallel to each other, so that the equation: θ4 = θ2 = θ3 holds,
Since the angle between rays does not change in plane reflection, the equation: θ1
= Θ4 holds. Therefore, the formula: θ1 = θ2 = θ3
= Θ4 holds. The permissible amount of eye movement as a finder is proportional to the exit angle θ1 from the micro prism (13a).

[0007]

In the above conventional example, the surface (1)
A large space for disposing the light projecting lens (19) and the like is required in the upper part of 2a). In a general single-lens reflex camera, since a built-in flash is mounted in this portion, if the effective diameter of the light projecting lens (19) is large, the camera becomes large. Conversely, if the effective diameter of the light projecting lens (19) is small, the pupil diameter at which the distance measurement point display can be observed will be small. For this reason, if the user slightly shakes his or her eyes while observing the viewfinder image, a fatal problem occurs in that the distance measurement point display becomes invisible. Therefore, when the above-described conventional illumination display method is adopted, if an attempt is made to achieve both proper display in the finder screen and mounting of the built-in flash,
Increasing the size of single-lens reflex cameras is inevitable.

The present invention has been made in view of such circumstances, and provides a display device in a finder screen that can achieve both miniaturization of a single-lens reflex camera and proper display in a finder screen. The purpose is to:

[0009]

According to a first aspect of the present invention, there is provided a finder screen display device for superimposing and displaying information in a finder screen of a single-lens reflex camera. In addition, a microprism that configures the information in a display pattern is arranged near a finder image that configures the finder screen, and at least one surface of the microprism is configured by a surface having power only in one direction. Outside the finder optical path, a light source that emits illumination light, and a light projecting optical system that guides the illumination light to the microprism are disposed, and the reflected light from the illuminated microprism is A superimposed display is performed.

According to a second aspect of the invention, in the finder screen display device according to the first aspect, the surface having power in only one direction is a cylindrical surface.

According to a third aspect of the present invention, in the finder screen display device according to the first aspect of the present invention, at least one of the display patterns is a straight line portion perpendicular to a plane including incident light and reflected light with respect to the microprism. A linear portion of the display pattern is formed by at least two microprisms whose ridge lines are parallel to the linear portion.

According to a fourth aspect of the present invention, in the finder screen display device according to the first aspect of the present invention, a pentaprism for inverting the finder image is further disposed, and the pentaprism is provided with the light projecting optical system. Are partially joined.

According to a fifth aspect of the present invention, in the finder screen display device according to the first aspect of the present invention, a plurality of the light sources are provided, and at least two illumination lights are emitted by the one light projecting optical system. The light projecting optical system is shared by each light source so as to be guided to the prism.

According to a sixth aspect of the present invention, there is provided a finder screen display device for superimposing and displaying information in a finder screen of a single-lens reflex camera, wherein the finder screen is provided near a finder image constituting the finder screen. A filter film configured to display the information in a display pattern is arranged, and the reflectance of the filter film is configured to be higher than a part of the wavelength of visible light. A light source that emits illumination light of a wavelength having a high reflectance, and a light projecting optical system that guides the illumination light to the filter film. A pause display is performed.

According to a seventh aspect of the present invention, in the finder screen display device according to the sixth aspect of the present invention, the reflectance of the area other than the display pattern near the finder image is minimized with respect to the wavelength of the illumination light. A characteristic feature is that an antireflection film having a value is provided.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A display device in a finder screen embodying the present invention will be described below with reference to the drawings. FIG.
Is a finder for a single-lens reflex camera equipped with a multipoint AF function, and has a function of superimposing and displaying distance measurement point information in a finder screen. As shown in FIG. 1, the main components of this finder are a reticle (1), an SI (superimpose) screen (2), a pentaprism (3), an eyepiece optical system (4), a protective glass (5), Light source unit (6), mirror (7) and light projecting prism lens
(8).

A reticle located at a film equivalent position
(1) A finder image (not shown)
(Subject image) is formed, and the finder light beam emitted from the focusing screen (1) constitutes a finder screen (G) shown in FIG. Information displayed in the finder screen (G) is a distance measurement area, a light measurement area, and a distance measurement point described later.
The information displayed outside the viewfinder screen is a shutter speed, an aperture value, an exposure correction value, and the like, and is indicated by an off-screen display (D) as shown in FIG. The off-screen display (D) is composed of, for example, a luminous flux for off-screen display, which is incident from the bottom of the pentaprism (3) together with a finder luminous flux.

The distance measurement area is indicated by a distance measurement area display (F1), and the distance measurement area at the time of wide focus is indicated by the distance measurement area display (F1). The photometry area is indicated by a photometry area display (F2), and the photometry area at the time of spot photometry is indicated by the photometry area display (F2). Since the distance measurement area display (F1) and the photometry area display (F2) are composed of the marking frame pattern processed and formed on the reticle (1),
It is always fixed in the viewfinder screen without being turned off. These area displays (F1, F2) may be configured by providing a frame pattern on the optical surface near the reticle (1). For example, a frame pattern may be provided on the SI screen (2), or a flat plate or a condenser lens on which the frame pattern is formed may be provided in the vicinity of the reticle (1).
A display element such as D may be used.

The finder light beam emitted from the focusing screen (1) passes through the SI screen (2), and then enters the pentaprism (3) from the surface (3b). This penta prism (3)
Is an inversion prism that inverts the finder image on the reticle (1) to make an upright image. The finder luminous flux incident on the pentaprism (3) and reflected by the three reflecting surfaces passes through the eyepiece optical system (4) and the protective glass (5) and reaches the pupil (E).

On the other hand, a light source unit (6), a mirror (7), a mask member (not shown), and a light projecting prism lens (8) are arranged outside the finder optical path in front of the pentaprism (3). The light source unit (6) includes nine LEDs (6a) as illumination light sources. The illumination light emitted from each LED (6a) is reflected by the mirror (7) substantially parallel to the surface (3a) of the pentaprism (3). The illumination light reflected by the mirror (7) enters a mask member (not shown) arranged near the light projecting prism lens (8). For the mask member,
Nine openings are provided at positions corresponding to the illumination light from each LED (6). Therefore, nine illumination light fluxes are emitted from the mask member, and both light projection prism lenses (8)
Will be incident. Here, one light projecting prism lens (8) is configured to be shared by each of the nine LEDs (6a), but two or more light projecting prism lenses (8) may be used if necessary. May be used.

The surface of the light projecting prism lens (8) on the mirror (7) side corresponds to the lens surface (the surface (8a) in FIG. 5) that is convex toward the mirror (7). }It has become. The illumination light passing through the lens surface (8a) is reflected on the plane reflecting surface of the projection prism lens (8) {FIG.
It corresponds to the middle surface (8b). }, The light is totally reflected toward the pentaprism (3), and then exits from the light projecting prism lens (8).
The exit surface of the light projecting prism lens (8) is joined to the surface (3a) of the pentaprism (3) as shown in FIG.
The illumination light is emitted from the light projecting prism lens (8) and simultaneously enters the pentaprism (3) from the surface (3a). This surface (3a) is a surface surrounded by the three reflecting surfaces of the pentaprism (3), and is not used as a surface that performs an optical function for image inversion.

The illumination light entering the pentaprism (3) from the surface (3a) exits the pentaprism (3) from the surface (3b) and then enters the SI screen (2). Side view of finder image of SI screen (2) {ie viewfinder screen
(G) is located near the viewfinder image}.
A microprism (2a) that forms distance measurement point information in a display pattern (that is, an AF frame) is formed. As shown in FIG. 2, the microprism (2a) has two reflecting surfaces, one of which is a cylindrical surface (2r). SI
Part of the illumination light incident on the screen (2) is totally reflected by the microprism (2a) to become a display light flux, and merges with the finder light flux. As a result, as shown in FIG.
AF point display (f1-f9) consisting of frames is displayed on the viewfinder screen.
(G) will be introduced as a superimposed display. This focus detection point display (f1 to f9) is illuminated when a specific operation (that is, automatic selection of focus detection points by the camera or manual selection of focus detection points by the photographer) is performed,
The selected distance measuring point is displayed by light emission.

As described above, the microprism (2a) arranged near the finder image has one surface which is a cylindrical surface.
(2r). Since this cylindrical surface (2r) is a concave reflecting surface having power only in one direction, the illumination light
(In FIG. 1 and FIG. 2, parallel to the paper). As described above, when the microprism (2a) is configured with a surface having power only in one direction, a controlled diffusion effect can be generated. Therefore, the effective diameter of the light projecting prism lens (8) can be reduced in the direction perpendicular to the surface (3a), and the width of the optical path near the light projecting prism lens (8) can be narrowed. Therefore, the surface (3a)
A sufficient free space for mounting the built-in flash on the top can be secured. Further, even if the effective diameter of the projecting prism lens (8) is small in the direction perpendicular to the surface (3a), a sufficient pupil diameter can be secured (the exit angle θ1 in FIGS. Therefore, it is possible to achieve both miniaturization of the single-lens reflex camera and proper display in the viewfinder screen.

As can be seen from FIGS. 1 to 3, the ridge lines of the microprism (2a) are all formed of straight lines parallel to the horizontal lines on the finder screen (G). It is constituted by a straight line portion perpendicular to a plane including incident light and reflected light with respect to the microprism (2a) (that is, parallel to a horizontal line on the finder screen (G)). In the SI screen (2) shown in FIG.
The linear portion of the AF frame is constituted by one microprism (2a) whose ridge line is parallel to the linear portion.
It is desirable that the linear portion of the AF pattern be constituted by one microprism. Three micro prisms (2b)
FIG. 4 shows an example in which the above-mentioned straight line portion is formed.

The reason why the linear portion parallel to the horizontal line is preferably composed of a plurality of microprisms as described above will be described below. The focus detection points selected as described above are displayed with the light reflected from the illuminated microprism (2a), but the focus detection points not selected are displayed in the viewfinder finder screen (G). Is displayed as a black line. This is because the microprism (2a) is not illuminated, and the finder light reflected by the microprism (2a) does not enter the pupil (E). When a linear portion parallel to the horizontal line is formed by a single row of microprisms (2a), only a part of the light reflected by the cylindrical surface (2r) enters the pupil (E), so when not illuminating (when the light source is off) Of the above black line (that is, a part in the line width direction). If the linear portion of the AF frame is composed of a plurality of microprisms (2b) as shown in FIG. 4, it is possible to display a horizontal line with fine lines at sufficiently small intervals, and as a finder image, the line width at the time of non-illumination Almost everything appears to be emitting light.

In a conventional finder in which light is not projected from the surface (3a) of the pentaprism (3), the entire surface (3a) of the pentaprism (3) is coated with a coating for preventing reflection on the back surface. You. Therefore, if the superimposed display is to be performed by projecting light from the surface (3a) as in the present embodiment, a part of the painted portion of the surface (3a) requires a window. In this case, if air is present between the pentaprism (3) and the projecting prism lens (8), the ghost image is formed as shown in FIG.
(GL: ghost optical path) occurs. If the position of the surface (3a) is set so that the pentaprism (3) becomes larger, this ghost can be prevented, but the camera becomes larger and the space for the built-in flash can be secured. Disappears. In order to solve this problem, in the present embodiment, a part of the light projecting prism lens (8) is joined to the pentaprism (3). When the light projecting prism lens (8) is joined to the surface (3a), there is no air between the opposing surfaces, so that total reflection causing ghosting is prevented. In FIG. 5, the light projecting prism lens (8) and the mask member (9) are drawn relatively large in order to show a state where the light projecting prism lens (8) and the pentaprism (3) are spaced apart. It is.

Next, another embodiment will be described with reference to FIG. The finder shown in FIG. 6 is also a finder for a single-lens reflex camera equipped with a multi-point AF function, and has a function of superimposing and displaying distance measurement point information in a finder screen. The obtained finder visual field is the same as in the case of the above embodiment (FIG. 3). Therefore, in the following description, the same portions or corresponding portions as those of the above-described embodiment will be denoted by the same reference numerals, and duplicate description will be omitted as appropriate.

As shown in FIG. 6, the main components of this finder are a reticle (1), an SI screen (2F), a pentamirror (3M), an eyepiece optical system (4), a light source unit (6), mirror
(7) and the projection lens (8A). On the reticle (1) arranged at the film equivalent position, a photographic lens (not shown)
The viewfinder image (subject image) is formed by
A finder screen (G) shown in FIG. 3 is constituted by the finder light beam emitted from (1). The finder light beam emitted from the reticle (1) passes through the SI screen (2F),
The light enters the pentamirror (3M). This pentamirror (3M)
Is a hollow penta type inversion optical system which inverts the finder image on the reticle (1) to make an erect image. The finder luminous flux incident on the pentamirror (3M) and reflected by the three reflecting surfaces passes through the eyepiece optical system (4) and the like and reaches the pupil (not shown).

On the other hand, the light source unit (6), the mirror (7), and the mask member are located outside the finder optical path in front of the pentamirror (3M).
(Not shown) and a light projecting lens (8A). The LED constituting the light source unit (6) has an emission wavelength peak at 650 nm. Illumination light emitted from the light source unit (6) is reflected by a mirror (7), and then enters a pentamirror (3M) through a mask member (not shown) and a projection lens (8A). This pentamirror (3M) is advantageous in reducing the weight of the camera, and also has a projection lens (8A)
Can be placed in the space inside the pentamirror (3M), which is advantageous in securing a sufficient empty space for mounting the built-in flash and reducing the size of the camera.

The illumination light that has entered the pentamirror (3M) and has been reflected once exits the pentamirror (3M), and then enters the SI screen (2F). This SI screen (2F)
Filter film (L1) and antireflection film (L) on curved substrate (L0)
2) is formed. Filter membrane (L1)
Constitutes an AF frame for displaying distance measuring points (f1 to f9),
The anti-reflection film (L2) is used for the SI
Prevents reflection of illumination light on the screen (2F). Part of the illumination light incident on the SI screen (2F) is
The light is reflected at 1) to become a display light flux and merges with the finder light flux. As a result, as shown in FIG. 3, the ranging point display (f1 to f9) including the AF frame is introduced as a superimposed display in the finder screen (G). In addition, it is possible to make the display luminous flux for all the distance measurement point displays (f1 to f9) enter the pupil by the curvature of the SI screen (2F).

The function of the SI screen (2F) will be described in more detail. Side viewfinder image side of SI screen (2F)
A filter film (L1) that forms distance measurement point information in a display pattern (that is, an AF frame) is formed on {a surface located near a finder image forming the finder screen (G)}, and the filter film is formed. The reflectivity of the film (L1) is configured to be higher than a part of the wavelength of visible light (wavelength near 650 nm). Since the light source (6A) located outside the finder optical path emits illumination light of a wavelength (650 nm) having a high reflectance at the filter film (L1), almost all of the illumination light incident on the filter film (L1). Is reflected and the bright AF point display (f1
To f9) are achieved. Also, when not illuminating (when the light source is OFF),
Since only a part of the wavelength (650 nm) of the finder light beam (visible light) is reflected by the filter film (L1), the distance measurement point display (f1 to f9) becomes almost invisible. Therefore, the disadvantage that the composition setting is disturbed by unnecessary display is eliminated.

On the other hand, on the side of the viewfinder image of the SI screen (2F) except for the AF frame, an anti-reflection film having a minimum value of the reflectance with respect to the wavelength (650 nm) of the illumination light is provided.
(L2) is provided. A on SI screen (2F)
If the reflectance of the region other than the F frame is high, the illumination light that has entered that region is reflected and enters the pupil, which may cause flare in the distance measurement point display (f1 to f9). Anti-reflection coating (L2) with strong anti-reflection effect against illumination light
By applying it on (L0), this can be prevented.

[0033]

As described above, according to the finder screen display apparatus of the present invention, it is possible to achieve both miniaturization of the camera and proper finder screen display. For example, even when this device is applied to a single-lens reflex camera with a built-in flash mounted on the upper part of the pentaprism, it is possible to achieve both proper display in the viewfinder screen and mounting the built-in flash without increasing the size of the camera It is.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic optical configuration of a finder to which an embodiment of the present invention is applied.

FIG. 2 is a cross-sectional view showing an example of a microprism used in the viewfinder of FIG. 1 and an optical path thereof.

FIG. 3 is a view showing an example of a viewfinder field of FIG. 1;

FIG. 4 is a sectional view showing another example of a microprism used in the finder shown in FIG. 1 and an optical path thereof.

FIG. 5 is a cross-sectional view showing a schematic optical configuration of a finder for explaining generation of a ghost.

FIG. 6 is a sectional view showing a schematic optical configuration of a finder to which another embodiment of the present invention is applied.

FIG. 7 is a cross-sectional view showing a conventional finder configuration example.

FIG. 8 is a sectional view showing a microprism used in the finder shown in FIG. 7 and its optical path.

[Explanation of symbols]

 G: Finder screen F1: Distance measurement area display F2: Metering area display f1-f9: Distance measurement point display D: Off-screen display E: Pupil 1: Focusing plate 2: SI screen 2a: Micro prism 2r: Cylindrical surface (one direction) 2F… SI screen L0… Substrate L1… Filter film L2… Anti-reflection film 3… Penta prism 3a… Surface 3M… Penta mirror 4… Eyepiece optical system 5… Protective glass 6… Light source unit 6a… LED (Light source) 7 Mirror 8 Projection prism lens (projection optical system) 8A Projection lens (projection optical system) 9 Mask member

Continued on the front page F term (reference) 2H018 AA26 BE02 2H042 CA00 CA18 2H087 KA14 LA12 PA02 PB02 QA02 QA07 QA17 QA21 QA34 QA42 RA41 RA42 2H102 AA41 AA42 AA44 BA01 BA12 BB00 BB05 BB22 CA14 CA26 CA27

Claims (7)

[Claims] 1. A display device in a finder screen for superimposing and displaying information in a finder screen of a single-lens reflex camera, comprising:
A microprism configured to display the information in a display pattern is provided, and at least one of the microprisms is arranged.
The surface is composed of a surface having power only in one direction, and a light source that emits illumination light and a light projection optical system that guides the illumination light to the microprism are arranged outside the finder optical path. A display device in a finder screen, wherein the superimposed display is performed by the reflected light from the illuminated microprism. 2. The display device according to claim 1, wherein the surface having power only in one direction is a cylindrical surface. 3. A display device according to claim 2, wherein at least a part of the display pattern is formed by a straight line perpendicular to a plane including the incident light and the reflected light with respect to the microprism, and at least two ridge lines are parallel to the straight line. 2. The display device in a finder screen according to claim 1, wherein the linear portion of the display pattern is constituted by one microprism. 4. The finder according to claim 1, further comprising a pentaprism for inverting the finder image, wherein a part of the light projecting optical system is joined to the pentaprism. In-screen display device. 5. A plurality of the light sources are provided, and the light-projecting optical system is shared by the light sources so that at least two illumination lights are guided to the microprism by the one light-projecting optical system. The display device in a finder screen according to claim 1, wherein: 6. A display device in a finder screen for superimposing and displaying information in a finder screen of a single-lens reflex camera, comprising:
A filter film that configures the information in a display pattern is arranged, and the reflectance of the filter film is configured to be higher with respect to a part of the wavelength of visible light. A light source that emits illumination light having a high reflectance and a light-projecting optical system that guides the illumination light to the filter film are arranged,
The display device in a finder screen, wherein the superimposed display is performed by reflected light from the filter film illuminated. 7. An anti-reflection film having a minimum value of reflectance with respect to the wavelength of the illumination light is provided in a region except for the display pattern in the vicinity of the finder image. Display device in the finder screen as described.