JPH05173224A - Finder screen of single-lens reflex camera - Google Patents

Abstract

PURPOSE:To provide a screen pattern according to various kinds of photographing use by employing a light-scattering liquid crystal to a finder screen, thereby making it unnecessary to change the finder screen. CONSTITUTION:A light-scattering liquid crystal 5 is held between transparent plates 4. The scattering degree of the light-scattering liquid crystal 5 is changed, and at the same time, a transparent electrode 6 to specify the scattering region is pattern-formed on the transparent plates 4. The transparent electrode 6 is connected to a driving circuit 2, and a control voltage is applied. The light- scattering liquid crystal 5 has a characteristic where the scattering performance of the luminous flux is changed according to the voltage to be applied, and a screen pattern according to various photographing use can be obtained by applying the voltage from the driving circuit 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a viewfinder for a single lens reflex camera.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional viewfinder in a single lens reflex camera. A lens 31 is provided on the light flux incident side of the finder barrel 30 and the finder barrel 30
A reflecting mirror 32 for reflecting the light flux upward is provided inside the. Further, a finder screen 33 and a pentaprism 34 are provided on the reflection optical path of the reflecting mirror 32, and an eyepiece 35 is provided on the luminous flux exit side of the pen prism 34. In such a configuration, the light flux incident from the lens 31 is reflected by the reflecting mirror 32 and forms an image on the finder screen 33. Therefore, by observing the image on the screen 33 through the pentaprism 34 and the eyepiece 35, The focal length can be adjusted. Since the finder screen 33 is applied to various objects to be photographed, it can be exchanged depending on the intended use. This exchange is performed by removing the pentaprism 34 or by directly taking it out from the reflecting mirror 32 side. .

4 to 8 each show a finder screen used according to the object to be photographed. FIG. 4 shows a viewfinder screen 33 for general photography, in which a microlens 36 for focusing is provided at the center and a peripheral surface of the microlens 36 is a diffusion surface 37. FIG. 5 shows a viewfinder screen 33 for close-up photography, which has a matte diffusion surface 37 on the entire surface. 6 and 7 show a viewfinder screen 33 for microscopic photography.

In microscope photography, the aerial image formed at the position of the finder screen is observed directly with a magnifying glass for focusing, and the screen used at this time has a transparent glass-like central part as shown in FIG. And a cross-shaped mark 38 is engraved at that position, or
A transparent glass whose entire focusing surface is transparent is selected. Further, when an auxiliary scale is required for the inclination and arrangement of the object to be photographed in the finder, a grid screen having grid lines on the finder screen as shown in FIG. 8 is used.

[0005]

The viewfinder of the conventional single-lens reflex camera has various viewfinder screens depending on the shooting application, and the plurality of viewfinder screens corresponding to the shooting application are used because the viewfinder screens are exchanged as needed. You need to prepare. Moreover, in order to replace the finder screen, it is necessary to operate other members such as removing the pentaprism 34, and the replacement work is troublesome.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a viewfinder screen of a single-lens reflex camera which can reduce the frequency of replacement.

[0007]

In order to achieve the above object, the present invention is to electrically change the screen surface according to the purpose of photography, and a light-scattering liquid crystal sandwiched between transparent plates.
A transparent electrode patterned on the transparent plate for changing the degree of scattering of the light-scattering liquid crystal and specifying a scattering site; and a drive circuit for applying a control voltage to the transparent electrode. To do.

[0008]

1 shows an embodiment of the present invention, which comprises a finder screen 1, a drive circuit 2 for driving the screen 1, and a display section 3. The finder screen 1 is arranged at a predetermined position inside the finder cylinder as shown in FIG. The finder screen 1 is composed of a polymer network liquid crystal display device having upper and lower transparent plates 4 such as transparent glass and a light-scattering liquid crystal 5 sandwiched between the transparent plates 4. The light-scattering liquid crystal 5 is a liquid crystal having a characteristic that the light-scattering performance is changed by the applied voltage as described in the material of the Japan Society for the Promotion of Science, Organic Materials for Information Science, 142th Committee, 49th Joint Research Meeting. is there. In order to operate the light-scattering liquid crystal 5, a transparent electrode 6 is formed on the surface of the transparent plate 4 on the light-scattering liquid crystal 5 side.
Are formed respectively.

FIG. 3 shows a transparent electrode 6 formed on a transparent plate 4, and a grid mat electrode pattern 6a is formed, and a central transmission electrode pattern 6b is formed at the center of the grid mat electrode pattern 6a. A cross-shaped electrode pattern 6c for focusing is formed. The drive circuit 2
Is to apply a control voltage to the transparent electrode 6 of such a transparent plate 4. In FIG. 1, 7 and 8 are switches. When the switch 7 is turned on, a high control voltage is applied to the transparent electrode 6, while when the switch 8 is turned on, a low control voltage is applied to the transparent electrode 6. And the display unit 3
Displays the voltage value applied from the drive circuit 2 to the transparent electrode 6 in a visible manner.

In the above structure, by controlling the voltage applied to the transparent electrode 6 by the drive circuit 2, a single finder screen 1 can form a screen suitable for various purposes. For example, in the case of a full mat screen, a voltage is applied so that the entire screen has a uniform scattering degree. At this time, even if an electrode pattern for another screen is formed on the transparent electrode 6, the entire electrode is transparent, so that a uniform scattering surface can be obtained. In the case of the central transmission type microscopic photographing screen, a voltage is applied so that the central transmission electrode pattern 6b is in a transmissive state and the peripheral portion is a diffusion surface. At this time, a cross-shaped mark is formed in a diffused state for focusing with a magnifying glass. This can be done by applying a voltage to the crosshair electrode pattern for focusing.
In the case of a screen for full-face transmission type microscopic photography, the entire screen is used as a transmission surface. At this time, a cross-shaped mark for focusing with the loupe is formed in a diffused state. In the case of a grid mat screen, it is formed by applying a voltage to the grid mat electrode pattern 6a. At this time, when it is necessary to use the entire mat screen together, a voltage is applied so that the grid mat electrode pattern and the other electrode patterns have the same diffusion degree. In the present embodiment, when a microlens is required at the central portion as shown in FIG. 4, the finder screen is equipped with the microlens.

The present invention is not limited to a single-lens reflex camera, but can be applied as a screen for various image-related equipment which requires a diffusing surface.

According to the present invention, since the light-scattering liquid crystal is used for the finder screen, it is possible to electrically control the scattering property of the finder screen. Therefore, the functions of various finder screens can be exhibited by merely operating the electric switches without replacing the finder screen.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a front view showing a pattern of a transparent electrode.

FIG. 3 is a cross-sectional view showing a conventional finder.

FIG. 4 is a front view of a finder screen.

FIG. 5 is a front view of a finder screen.

FIG. 6 is a front view of a finder screen.

FIG. 7 is a front view of a finder screen.

FIG. 8 is a front view of a finder screen.

[Explanation of symbols]

 1 Finder screen 2 Drive circuit 4 Transparent plate 5 Light-scattering liquid crystal 6 Transparent electrode

Claims (1)

[Claims] 1. A light-scattering liquid crystal sandwiched between transparent plates, a transparent electrode patterned on the transparent plate to change a scattering degree of the light-scattering liquid crystal and identify a scattering site, and the transparent electrode. A finder screen for a single-lens reflex camera, comprising a drive circuit for applying a control voltage to the.