JP5326598B2 - Camera with viewfinder display function by optical scanning - Google Patents

Description

  The present invention relates to a camera including an optical finder such as a pentaprism, and more particularly to a finder display mechanism capable of superimposing character information and the like by two-dimensional scanning using a micromirror.

  In a single-lens reflex camera, light passing through a photographing lens is guided to a focus glass above the mirror by a quick return mirror, and a subject image is formed on the focus glass. The subject image can be observed by a pentaprism or a pentamirror provided on the upper part of the camera, and the composition and focus state of the subject are confirmed through the eyepiece.

  Above the focus glass, a screen plate on which a plurality of minute prisms are formed at the distance measuring point position is arranged in order to display the in-focus position and the like in the viewfinder field of view. When autofocus functions by half-pressing the release button, light is emitted from a light source such as an LED provided near the viewfinder toward the in-focus position, whereby the in-focus mark is superimposed on the subject image. In addition, exposure values such as aperture and shutter speed are displayed outside the viewfinder field by the liquid crystal element.

  The display position of the focus mark can be displayed only at the position where the minute prism is formed, and the display position of the character information is also determined in a predetermined area outside the viewfinder field of view. In order to eliminate such a restriction on the display position of the pattern, a camera finder display method in which a micromirror is arranged together with a liquid crystal element is known (see Patent Document 1).

  There, the light from the LED light source is irradiated onto a micromirror inclined at a predetermined angle, and the reflected light is superimposed on the light of the subject image. The pattern display position such as the focus point is controlled by adjusting the angle of the micromirror.

JP-A-11-15063

  Since the light from the light source is viewed as it is through a mirror or the like, there is a safety problem depending on the type of the light source. For example, when using a laser light source, the camera must be manufactured according to strict safety standards.

  Also, as a camera finder function, it is necessary to make the pattern visible regardless of the viewing angle, but since the light reflected by the micromirror is generally highly directional, it is an optical lens that diverges light (power) Therefore, the structure of the camera is complicated and the light efficiency of the optical viewfinder is lowered.

  The camera of the present invention is a camera capable of finder display, such as a single-lens reflex digital camera, has a focusing screen, includes an optical finder that forms a subject image for observation, and emits light in a predetermined wavelength region. By tilting a light source and a minute mirror that reflects the light from the light source, a scanner mechanism that scans the light reflected by the minute mirror in accordance with a viewfinder field, and a display pattern is formed by modulating the light from the light source. Display control means. For example, the micromirror is irradiated with light by a laser light source, and the reflected light is two-dimensionally scanned (raster scanning) by controlling the tilt angle of the micromirror that can rotate about two orthogonal axes.

  Furthermore, the camera of the present invention is disposed along an optical member that reflects visible light while transmitting visible light (hereinafter referred to as a first optical member), and a reflection direction of the first optical member, and the light source An optical member (hereinafter, referred to as a second optical member) having a fluorescent material that emits fluorescence when excited by the light. The first and second optical members are positioned with respect to the optical viewfinder so that a display pattern by the fluorescence transmitted through the first optical member is displayed so as to overlap the subject image in the optical viewfinder. Yes.

  In this invention, the 2nd optical member only for pattern display is provided, and the light according to a pattern is irradiated to a 2nd optical member through a 1st optical member. When light strikes the phosphor formed on the surface of the second optical member, the fluorescent light, which is visible light, passes through the first optical member and travels into the optical viewfinder. Then, the display pattern is superimposed on the subject image in the viewfinder field by overlapping with the light of the subject image. When fine character information is included as a display pattern, the second optical member is preferably arranged at a position optically equivalent to the focusing screen with respect to the optical path length in order to display a clear display pattern.

  Since the fluorescence emitted without strong directivity is incident on the finder optical system, the display pattern can be clearly seen even when the finder's viewing angle is different. In addition, since the phosphor is not formed on the surface of the focusing screen, it is possible to display a bright subject image in a finder display without degrading the optical characteristics of the focusing screen. Furthermore, since the light of the display pattern visually recognized by the user is fluorescent, there is no safety problem.

  In order to emit fluorescence in a diffused state with as little directivity as possible, the second optical member is preferably a mat plate coated with the phosphor. On the other hand, as the first optical member, it is preferable to provide a dichroic mirror that selectively reflects and transmits a specific wavelength. For example, when the light source emits far infrared rays, a wavelength selection filter that selectively reflects far infrared rays such as a cold filter may be disposed.

  The viewfinder mechanism of the present invention can be mounted on a camera or the like, has a focusing screen, forms an object image for observation, and reflects light of a light source reflected on a micromirror, while reflecting visible light. A first optical member that transmits the second optical member, and a second optical member that is disposed along a reflection direction of the first optical member and that emits fluorescence when excited by light of the light source; The first and second optical members are positioned with respect to the optical viewfinder so that a display pattern by fluorescence transmitted through the optical member is displayed over the subject image in the viewfinder field.

  As described above, according to the present invention, it is possible to display a finder with a simple structure and excellent visibility without any problem in safety.

It is a partial internal block diagram of the digital camera which is this embodiment. It is a block diagram of a digital camera. It is the figure which showed the finder display in the state where the release button was half-pressed.

  Below, the digital camera which is this embodiment is demonstrated with reference to drawings.

  FIG. 1 is a partial internal configuration diagram of a digital camera according to the present embodiment.

  In the single-lens reflex digital camera 10, a photographing optical system 12 including a lens barrel is detachably attached to the camera body 11. A quick return mirror 13, a focal plane shutter (not shown), A CCD 14 is arranged. Above the mirror box in which the quick return mirror 13 is disposed, an optical viewfinder 20 including a focus glass 24 having a mat surface 25, a pentaprism (pentagonal roof prism) 26, and a loupe optical system 22 is disposed.

  The light passing through the photographing optical system 12 is guided upward by the quick return mirror 13, and a subject image is formed on the focus glass 24. The light passing through the focus glass 24 is reflected in the pentaprism 26 and guided to the loupe optical system 22. Thereby, the optical image of the subject captured by the photographing optical system 12 is visually recognized through the loupe optical system 22.

  A columnar prism 28 is disposed in front of the pentaprism 26 (imaging optical system), and one end surface 28A is in contact with the second reflecting surface 26B of the pentaprism 26. Inside the prism 28, a cold filter 30 that reflects far infrared rays and transmits visible light is disposed. Further, a mat plate (screen plate) 40 in which the phosphor 40 is coated on the mat surface 40S is disposed in the vicinity of the other end surface 28B of the prism 28.

  The scanner mechanism 50 disposed above the prism 28 includes a micromirror device 55 and a laser light source 60, and the micromirror 56 is disposed with its reflecting surface facing the prism 28. The laser light source 60 emits a far-infrared light beam, and the far-infrared light converted into parallel light by the collimator lens 52 is reflected by the micromirror 56.

  The micromirror device 55 is a microdevice in which a micromirror 56 is integrally formed on a silicon wafer substrate (not shown) that is a support frame, and two pairs of hinges and torsion bars (not shown) that connect the support frame and the micromirror 56. Z)). Here, the micromirror 56 is capable of axial rotation and reciprocating swing around the hinges formed along two orthogonal axes, and is tilted two-dimensionally with respect to a reference plane along the substrate.

  By generating positive and negative charges between a fixed electrode (not shown) attached to the support frame and a movable electrode (not shown) attached to the micromirror 56, the micromirror 56 tilts, and the charge amount is reduced. By adjusting, the inclination angle changes continuously. Here, the micromirror 56 is driven two-dimensionally so that the light of the display pattern performs raster scanning in accordance with the viewfinder field.

  Far-infrared light reflected by the micromirror 56 is reflected by the cold filter 30 and travels toward the mat plate 40 disposed in the reflection direction. The mat plate 40 is a glass plate having the same size as the focus glass 24 and is disposed at an optically equivalent position in the direction of the optical axis E with respect to the focus glass 24. The mat plate 40 is coated with a phosphor 42 on the surface of the mat surface 40S that diffuses and reflects light, and the far-infrared light incident on the mat plate 40 becomes fluorescence that is visible light by excitation. Diffuse reflection.

  Therefore, when far-infrared light reflected by the cold filter 30 hits the mat surface 40S, fluorescent light (for example, red light) that diffuses without directivity is emitted and travels toward the cold filter 30. The cold filter 30 transmits fluorescence that is visible light, and light having a display pattern due to fluorescence enters the optical finder 20.

  The mat plate 40 is in an optically equivalent position to the focus glass 24, and the optical path length between the focus glass 24 and the loupe optical system 22 is equal to the optical path length between the mat plate 40 and the loupe optical system 22. Further, the cold filter 30 and the mat plate 40 are disposed so that the centers thereof coincide with the optical axis E, and the mat plate 40 is disposed at an optically equivalent position to the focus glass 24 in the optical axis direction. The optical image by fluorescence overlaps with the optical image formed on the focus glass 24 through the loupe optical system 22.

  FIG. 2 is a block diagram of the digital camera 10. FIG. 3 is a view showing a finder display in a state where the release button is half-pressed.

  When the main switch S1 is turned on by the power ON operation, power is supplied from the power circuit 82 to the entire circuit including the system control circuit 80. A system control circuit 80 including a ROM 97 and a RAM 99 controls camera operation and outputs a control signal to the AF control unit 90, the split photometry control unit 98, and the like. The subject image formed by the photographing optical system 12 is displayed through the loupe optical system 22.

  When a release button (not shown) is pressed halfway and the photometry switch S2 is turned on, the brightness of the subject is measured by the divided photometry control unit 58, and the exposure value is calculated. When the light passing through the photographing optical system 12 is guided to the AF CCD sensor 91 provided at the lower part of the mirror box, the AF control unit 90 detects whether or not it is in focus. In accordance with the multi-segment autofocus function, the system control circuit 80 controls the AF motor 93 to shift the focusing lens of the photographing optical system 12.

  On the other hand, for finder display, the laser drive circuit 61 drives the laser light source 60 and far-infrared laser light is emitted toward the micromirror 56. Further, the mirror drive circuit 57 controls the micromirror device 55 to drive the micromirror 56 two-dimensionally and raster scan the reflected light of the micromirror 56.

  As described above, the far-infrared light reflected by the micromirror 56 is reflected by the cold filter 30 and applied to the mat plate 40. Then, the fluorescence generated from the phosphor 42 of the mat plate 40 passes through the cold filter 30 and enters the pentaprism 26 and is superimposed on the light of the subject image.

  The raster scanning range by the micromirror 56 follows the field of view of the subject image displayed in the viewfinder. In addition, the inclination angle of the micromirror 56 with respect to the two axes has a one-to-one correspondence with the scanning position in the finder field area. Therefore, by controlling ON / OFF of the light emitted from the laser light source 60 at a predetermined timing, it is possible to display patterns such as characters and marks at a desired size and position.

  The system control circuit 80 outputs a control signal to the laser drive circuit 61 in order to display the display pattern at a predetermined size and a predetermined position. The laser drive circuit 61 controls ON / OFF of the laser light source 60, and switches the laser light source 60 ON when light scans the display position. Data relating to the size and display position of the display pattern is stored in the ROM 97 in advance.

  In FIG. 3, a frame-like focus mark K1 is superimposed on the focus position detected by the multi-segment autofocus operation together with the subject image displayed in the viewfinder. Further, the aperture value K2 and the shutter speed K3, which are exposure values, are superimposed on the display area near the right end.

  When the release button is fully pressed and the release switch S3 is turned on, a series of recording operations are executed, and the exposure control unit 95 retracts the quick return mirror 13 and opens and closes the shutter 55. As a result, a subject image is formed on the CCD 14. An image signal corresponding to the subject image is read from the CCD 14 by the CCD drive circuit 92. The signal processing circuit 99 performs various processes such as white balance, gamma correction, and matrix conversion on the read image signal, and generates digital R, G, and B image signals.

  The digital image signal is recorded on the memory card 88 after being compressed. When the playback mode is selected by operating a mode dial (not shown), the recorded image data is read from the memory card 88. Then, the image restored by the decompression process is reproduced and displayed on the LCD 96.

  As described above, according to the present embodiment, the scanner mechanism 50 including the cold filter 30, the mat plate 40, and the micromirror 56 is arranged with respect to the optical viewfinder 20. Far-infrared rays emitted from the laser light source 60 are reflected by the micromirror 56 and guided to the mat plate 40 by the reflection of the cold filter 30.

  Fluorescence is generated by irradiating far-infrared rays to the mat plate 40 coated with the phosphor 42, and passes through the cold filter 30 to overlap the light of the subject image in the pentaprism 26. The micromirror 56 is driven two-dimensionally to raster-scan the reflected light, and the light emission of the laser light source 60 is ON / OFF controlled at a predetermined timing. As a result, during the release half-pressed state, display patterns such as an in-focus mark and character information are superimposed on the subject image.

  Further, since the light from the laser light source 60 is not directly recognized, there is no safety problem. Furthermore, since the display pattern is formed not by visually recognizing the light reflected by the mirror but by the diffused fluorescence, the visibility is excellent even when the angle of looking through the viewfinder is changed. Particularly, since the mat plate 40 dedicated to the display pattern is provided on the focus glass 24 without coating the phosphor, a bright subject image can be displayed in the viewfinder without deteriorating the optical characteristics of the pentaprism 26.

  The arrangement relationship of the scanner mechanism, the cold filter, and the mat plate is not limited to the embodiment, and it may be configured such that the fluorescence is incident on the optical viewfinder so that the display pattern overlaps the subject image. For the display pattern formation, a light source other than a laser light source may be used, or light other than far-infrared light may be emitted. An optical member other than a cold filter may be used, and an optical member that reflects light from a light source and transmits fluorescence, such as a dichroic mirror, may be used. In addition to the character information, a recorded image or the like may be displayed in a finder.

  Further, the viewfinder mechanism of the present embodiment may be applied to a photographing apparatus having a viewfinder function other than a digital camera such as a movie camera.

10 Digital Camera 12 Imaging Optical System 20 Optical Viewfinder 24 Focus Glass
26 penta prism 30 cold filter (first optical member)
40 Matt plate (second optical member)
42 Phosphor 50 Scanner mechanism 56 Micro mirror (micro mirror)
60 Laser light source (light source)

Claims (7)

An optical viewfinder having a focusing screen and forming an object image for observation;
A light source that emits light in a predetermined wavelength region;
A scanner mechanism that scans the light reflected by the micromirror according to the viewfinder field by tilting the micromirror that reflects the light of the light source;
Display control means for modulating the light of the light source to form a display pattern;
A first optical member that reflects light from the light source and transmits visible light;
A second optical member that is arranged along the reflection direction of the first optical member and that has a fluorescent material formed on the surface thereof that emits fluorescence when excited by light from the light source;
The first and second optical members are positioned with respect to the optical viewfinder so that a display pattern by fluorescence transmitted through the first optical member is displayed superimposed on a subject image within the viewfinder field. Camera.   The camera according to claim 1, wherein the second optical member has a mat plate coated with the phosphor.   The camera according to claim 1, wherein the second optical member is disposed at a position optically equivalent to the focusing screen.   The camera according to claim 1, wherein the first optical member includes a dichroic mirror. The light source emits far-infrared rays;
The camera according to claim 1, wherein the first optical member has a wavelength selection filter that selectively reflects far infrared rays.   The camera according to claim 1, wherein the light source is a laser light source. An optical viewfinder having a focusing screen and forming an object image for observation;
A first optical member that reflects visible light while reflecting light from the light source reflected by the micromirror;
A second optical member that is arranged along the reflection direction of the first optical member and that has a fluorescent material formed on the surface thereof that emits fluorescence when excited by light from the light source;
The first and second optical members are positioned with respect to the optical viewfinder so that a display pattern by fluorescence transmitted through the first optical member is displayed superimposed on a subject image within the viewfinder field. Finder mechanism.

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