JP2000194053A - Display device within finder for single-lens reflex camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device within a finder of a single-lens reflex camera, that information to be displayed can be precisely displayed. SOLUTION: This display device within a finer of the single-lens reflex camera is constituted as follows. A semipermeable surface is adopted as the 3rd reflection surface 19b of a pentagonal prism 19 and an auxiliary prism 31 is stuck to the semipermeable surface. Then, a LCD panel 37 displaying information which should be displayed within a finder visual field, a projection lens 39 and an illumination light source 40 illuminating the panel 37 through the lens 39 are disposed in turn at the opposite side of the 3rd reflection surface of the prism 31. Besides, a diopter adjustment lens 33 making the position of the panel 37 optically equivalent to that of a focusing plate 15 is disposed between the prism 31 and the panel 37.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device in a finder of a single-lens reflex camera, and more particularly to a display device suitable for superimposing and displaying photographing information on a finder image (superimpose).

[0002]

2. Description of the Related Art As a conventional superimposed type display device in a viewfinder, for example, a device in which a deflecting element (reflection element) is partially provided on a focus plate and the deflecting element is illuminated by an LED is known. ing. However, in the display device in the finder, if the number of deflection elements formed on the focus plate is increased, it becomes difficult to arrange a large number of LEDs in a narrow area around the focus plate, and it is difficult to emit light in an area (deflection). It is also difficult to accurately guide the light flux to the element)
There has been a problem that the adjacent area also emits light at the same time.

[0003] Further, there is a type in which the focus plate itself is configured as a liquid crystal focus plate and information is displayed by liquid crystal. However, there is a problem that the finder itself becomes dark and it is difficult to visually recognize it.

Further, there is a type in which a half mirror is arranged between an eyepiece and a pentaprism or a pentamirror, and LED light is interrupted into an observation optical system via the half mirror. It greatly affects the basic performance of the viewfinder, such as deterioration and reduction of the eye relief.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a single-lens reflex camera for displaying various information in a finder visual field, a display device in the finder which can be easily viewed and accurately displayed while maintaining the basic performance of the finder. With the goal.

[0006]

SUMMARY OF THE INVENTION The present invention provides a display device in a finder utilizing a space in front of a third reflecting surface of a pentaprism or a pentamirror, which is relatively easy to take up space. There is a mirror correspondence mode. In the pentaprism corresponding mode, an auxiliary prism is adhered to the third reflection surface of the pentaprism as a semi-transmission surface, and an image is displayed in the viewfinder field in order on the opposite side of the third reflection surface of the auxiliary prism. An LCD panel for displaying information to be provided, a projection lens, and an illumination light source for illuminating the LCD panel via the projection lens,
A diopter adjusting lens is disposed between the auxiliary prism and the LCD panel to make the position of the LCD panel optically equivalent to the position of the focus plate.

In the pentamirror compatible mode, no auxiliary prism is required. In this embodiment, the third reflecting surface of the pentamirror is a semi-transmissive surface, and LCs for displaying information to be displayed in the viewfinder field are sequentially arranged outside the third reflecting surface.
D panel, a projection lens, and L
An illumination light source for illuminating the CD panel is provided, and a diopter adjusting lens for optically making the position of the LCD panel equivalent to the position of the focus plate is provided between the third reflection surface and the LCD panel. It is characterized by:

The projection lens can be downsized by being composed of a Fresnel lens, and the LCD panel can be more uniformly illuminated by making at least one surface aspherical. The semi-transmission surface of the third reflection surface is LC
In order to make the amount of light suitable for directly viewing the D panel, it is preferable to have a transmission characteristic of transmitting 5 to 20% of visible light or light of an illumination light source.

The display device in the finder according to the present invention is applied to a single-lens reflex camera having a multi-point distance measurement function, and if the distance measurement area mask is provided on the LCD panel, the distance measurement area mask can be displayed in the viewfinder. Can be.

[0010]

1 to 5 show a main part of a single-lens reflex camera to which a display device in a finder according to the present invention is applied. This embodiment is an embodiment in which a selected distance measurement area mask is displayed in a single-lens reflex camera with multipoint distance measurement using a pentaprism. The subject light flux from the photographing lens 11 is reflected by the main mirror 13 and forms an image on a focus plate 15 optically equivalent to a film surface (imaging surface) 17. The pentaprism 19 includes a roof reflection surface 19a that reflects the light beam from the focus plate 15 and a third reflection surface 19b. The light beam reflected by the third reflection surface 19b is guided to the eyepiece 21. As is well known, the roof reflection surface 19a and the third reflection surface 19b of the pentaprism 19 constitute a reflection surface for observing the subject image as an erect image together with the main mirror 13.

The main mirror 13 has a semi-transmissive surface (half mirror) at the center thereof, and the luminous flux transmitted through the half mirror is guided to the multipoint ranging AF module 25 via the sub mirror 23. The multi-point ranging AF module 25 calculates (measures) the defocus amounts in a plurality of ranging areas in the shooting screen (finder),
An AF driving system (not shown) drives the photographing lens 11 based on the defocus signal so as to focus on a subject in the selected ranging area. The above is a configuration example of a general multi-point distance-measuring single-lens reflex camera, which is well known.

In the above configuration, the pentaprism 19
The third reflective surface 19b is configured such that a certain range around the optical axis 21x of the eyepiece 21 is formed as a semi-transmissive surface (half mirror).
The auxiliary prism 31 is bonded. The auxiliary prism 31 is made of the same material as the pentaprism 19, and its exit surface 31a is orthogonal to the optical axis 21x of the eyepiece 21, and the optical axis 21x of the eyepiece 21 does not deflect (go straight) on the bonding surface. .

The optical axis 2 is located outside the auxiliary prism 31.
A diopter adjusting lens 33, a reflection mirror 35, an LCD panel 37, a projection lens 39, and an illumination light source 40 are sequentially arranged on the 1x optical axis. That is, the loupe optical axis (optical axis 21X) and the superimposed optical axis (optical axis of the diopter adjusting lens 33) are substantially coaxial. The diopter adjusting lens 33 having a positive power makes the position of the LCD panel 37 optically equivalent to the focus plate 15. The diopter adjusting lens 33 can be provided on the exit surface of the auxiliary prism 31.

The LCD panel 37 is orthogonal to the optical axis 21x. In this embodiment, as is apparent from FIG.
There are nine distance measurement area masks (information masks) 37a in three columns and three rows for multipoint distance measurement (9 points in this example), and opaque (non-light-transmitting) is always included in the distance measurement area mask 37a. Gender)
Liquid crystal that changes to light-transmitting when a driving voltage is applied is sealed. The illumination light source (LED) 40 includes a projection lens 39.
The LCD panel 37 is illuminated via the. The projection lens 39 gives the divergent light beam from the illumination light source 40 to the LCD panel 37 as a substantially parallel light beam, and even if any of the distance measurement area masks 37a changes to translucency, the distance measurement area mask 37
The light flux of the illumination light source 40 that has passed through a
The light enters the observer's eye via the auxiliary prism 31, the pentaprism 19, and the eyepiece 21.

FIG. 4 shows an example in which the projection lens 39 is configured as a Fresnel lens. At least one surface of the projection lens 39 is aspherical, so that more uniform light distribution characteristics can be obtained.

As shown in FIG. 5, the illumination light source 40 emits light via a control circuit 41 and an illumination light source driving circuit 43, and the LCD panel 37 is driven via the control circuit 41 and an LCD panel driving circuit 44. You. The control circuit 41 includes information from the distance measuring area selecting means 45 indicating which of the nine distance measuring areas to select, and the multi-point distance measuring AF module 2
The distance measurement information (defocus information) from No. 5 is input. The control circuit 41 applies a voltage to the liquid crystal corresponding to one of the selected distance measurement area masks 37a via the LCD panel drive circuit 44 based on the information, and simultaneously controls the illumination light source drive circuit 43. Light source 4 through
0 is emitted. The luminous flux from the illumination light source 40 passes through one of the ranging area masks 37a that are changing to translucency, reaches the reflection mirror 35, and passes through the diopter adjusting lens 33 and the auxiliary prism 31 into the pentaprism 19. After entering, it is observed through the eyepiece 21 together with the image on the focus plate 15. As the distance measurement area selection unit 45, a manual switch, a line-of-sight detection switch, and the like are known. In FIG.
A drive system of the photographing lens 11 driven by distance measurement information (defocus information) from the multipoint distance measurement AF module 25 is omitted.

The color of the illumination light source 40 is a color that can be seen when superimposed on the subject image on the focus plate 15, for example, red (wavelength;
About 600 nm). Third reflective surface 19b
The semi-transmissive film formed at the time of observing the subject image on the focus plate 15 is such a light transmission that the LED light flux that passes through the distance measurement area mask 37a and directly enters the eye does not disturb and can be clearly recognized. Characteristics. According to experiments, for example, a half coat having a property of transmitting light having a wavelength of about 600 nm at a transmittance of 5 to 20%, preferably about 10% is preferable. Such a light transmission characteristic is that even a coating having a uniform transmittance over the entire visible light region as shown in FIG. 7 transmits only about 10% of light having a wavelength of about 600 nm as shown in FIG. The rest can also be obtained with non-permeable coatings. Such coating techniques are well known.

The air path length of the optical path of the display optical system from the eyepiece 21 to the LCD panel 37 is shorter by the amount of passage through the pentaprism 19 and the auxiliary prism 31, so that the power of the diopter adjusting lens 33 can be reduced. it can. Further, the diopter adjusting lens 33 can adjust the diopter of the finder while shortening the entire length of the display optical system.
And the size of the display optical system can be reduced.

However, according to the present invention, the pentaprism 19
Instead of this, the present invention is also applicable to a pentamirror (a mirror having a cavity inside with a reflection surface corresponding to the roof reflection surface 19a and the third reflection surface 19b of the pentaprism 19). In this embodiment, the auxiliary prism 31 may be omitted.

FIG. 6 shows another example of the information mask attached to the LCD panel 37. From the upper left to the right, there are information masks for macro shooting, AF shooting, and automatic exposure shooting, from the lower left to the right, from the top left to the right, for program shooting, strobe shooting, strobe prohibition, backlight, and backlight.

[0021]

According to the present invention, it is possible to provide a small display device in a finder which can accurately display information to be displayed in a finder visual field without affecting the basic performance of the finder of the single-lens reflex camera. it can. In particular, it is suitable as a superimposed display device that superimposes information on a finder image.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a main part of a single-lens reflex camera having a display device in a finder according to the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a perspective view of the main part.

FIG. 4 is a perspective view showing an example of a relationship between an LCD panel having an information mask and an illumination light source.

FIG. 5 is a block diagram illustrating a control system of the camera in FIG. 1;

FIG. 6 is a plan view showing another example of the information mask.

FIG. 7 is a graph showing an example of transmittance characteristics of a semi-transmission surface of a third reflection surface.

FIG. 8 is a graph showing another example of the transmittance characteristics of the semi-transmission surface of the third reflection surface.

[Explanation of symbols]

 Reference Signs List 11 shooting lens 13 main mirror 15 focus plate 17 film surface (imaging surface) 19 pentaprism 19a roof reflection surface 19b third reflection surface 21 eyepiece 23 sub mirror 24 multipoint ranging AF module 31 auxiliary prism 31 third reflection surface 33 Degree adjusting lens 35 Reflecting mirror 37 LCD panel 37a Distance measuring area mask (information mask) 39 Projection lens 40 Illumination device 41 Control circuit 43 Illumination light source driving circuit 44 LCD panel driving circuit 45 Distance measuring area selecting means

Claims (5)

[Claims] A roof reflecting surface for reflecting a light beam from a focus plate at a position optically equivalent to an image forming surface of a taking lens;
In a display device in a viewfinder of a single-lens reflex camera including a pentaprism having a third reflecting surface that reflects the light beam reflected by the roof reflecting surface toward the eyepiece, the third reflecting surface is a semi-transmissive surface, An auxiliary prism is adhered to the semi-transmissive surface, and an LCD panel for displaying information to be displayed in the viewfinder visual field, in order, on the opposite side of the auxiliary reflecting surface of the auxiliary prism, a projection lens, and An illumination light source for illuminating the LCD panel is provided, and a diopter adjusting lens for optically making the position of the LCD panel equal to the position of the focus plate is provided between the auxiliary prism and the LCD panel. A display device in a viewfinder of a single-lens reflex camera, characterized in that: 2. A roof reflecting surface for reflecting a light beam from a focusing plate at a position optically equivalent to an image forming surface of a taking lens;
In a display device in a viewfinder of a single-lens reflex camera having a pentamirror having a third reflecting surface that reflects the light beam reflected by the roof reflecting surface toward the eyepiece, the third reflecting surface is a semi-transmissive surface, An LCD panel for displaying information to be displayed in the viewfinder field in order outside the third reflecting surface, a projection lens,
An illumination light source for illuminating the LCD panel via the projection lens is provided, and the position of the LCD panel is optically equivalent to the position of the focus plate between the third reflection surface and the LCD panel. A display device in a viewfinder of a single-lens reflex camera, wherein a diopter adjusting lens is provided. 3. The display device according to claim 1, wherein the projection lens comprises a Fresnel lens. 4. The finder display device according to claim 1, wherein the projection lens has an aspherical surface. 5. The display device in a finder according to claim 1, wherein the semi-transmission surface of the third reflection surface has a transmission characteristic of transmitting 5 to 20% of visible light or light of the illumination light source. Finder display device.