JPS57124331A - Liquid crystal focusing screen for camera - Google Patents
Liquid crystal focusing screen for cameraInfo
- Publication number
- JPS57124331A JPS57124331A JP1061981A JP1061981A JPS57124331A JP S57124331 A JPS57124331 A JP S57124331A JP 1061981 A JP1061981 A JP 1061981A JP 1061981 A JP1061981 A JP 1061981A JP S57124331 A JPS57124331 A JP S57124331A
- Authority
- JP
- Japan
- Prior art keywords
- liquid crystal
- focusing
- camera
- focusing screen
- screen
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B13/00—Viewfinders; Focusing aids for cameras; Means for focusing for cameras; Autofocus systems for cameras
- G03B13/18—Focusing aids
- G03B13/24—Focusing screens
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Viewfinders (AREA)
- Liquid Crystal (AREA)
Abstract
PURPOSE:To achieve detection of focus automatically, by making a liquid crystal screen opaque through power application, through the detection of focusing, in the focusing screen using liquid crystal. CONSTITUTION:In a camera having a liquid crystal plate 1 as a focusing screen, a comparator circuit 52 is connected to an ammeter terminal A in a bridge circuit, a low-level output is obtained to a voltage input being a certain range (taking O voltage as a center) corresponding to a focusing state by means of reference voltages 53, 54 and comparators 55, 56, the level is converted into a high level by an inverter 57, a liquid crystal plate is driven via an AC square wave generating circuit 51 to be opaque. At nonfocusing, no power is applied and the crystal plate is transparent, and the user can see a bright finder.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1061981A JPS57124331A (en) | 1981-01-26 | 1981-01-26 | Liquid crystal focusing screen for camera |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1061981A JPS57124331A (en) | 1981-01-26 | 1981-01-26 | Liquid crystal focusing screen for camera |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS57124331A true JPS57124331A (en) | 1982-08-03 |
Family
ID=11755233
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP1061981A Pending JPS57124331A (en) | 1981-01-26 | 1981-01-26 | Liquid crystal focusing screen for camera |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS57124331A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5333031A (en) * | 1991-08-21 | 1994-07-26 | Minolta Camera Kabushiki Kaisha | Camera having a liquid crystal focusing screen |
JPH075101U (en) * | 1993-06-25 | 1995-01-24 | 恵和商工株式会社 | Composite sheet material |
US5903788A (en) * | 1993-01-07 | 1999-05-11 | Minolta Co., Ltd. | Camera |
-
1981
- 1981-01-26 JP JP1061981A patent/JPS57124331A/en active Pending
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5333031A (en) * | 1991-08-21 | 1994-07-26 | Minolta Camera Kabushiki Kaisha | Camera having a liquid crystal focusing screen |
US5903788A (en) * | 1993-01-07 | 1999-05-11 | Minolta Co., Ltd. | Camera |
JPH075101U (en) * | 1993-06-25 | 1995-01-24 | 恵和商工株式会社 | Composite sheet material |
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