JP4548396B2 - camera - Google Patents

Description

  The present invention relates to a camera having a viewfinder for observing a subject.

2. Description of the Related Art Conventionally, a camera having a finder for observing a subject has a known configuration in which the position of a focus detection area or the like is superimposed on a subject image and displayed on the finder. Further, for example, as in Patent Document 1, a camera that can display a reference line for composition determination superimposed on a subject image of a finder is also known.
JP 2002-72333 A

  By the way, in camera shooting, there are cases where focusing and composition determination are completely different operations, for example, when a moving subject is placed and shot with a pin. In such a case, the priority of the reference line display is low at the focus adjustment stage, and conversely the display priority of the focus detection area is low at the composition determination stage. Therefore, there has been a demand for a camera that can switch the viewfinder display according to the shooting situation.

  The present invention is to solve the above-mentioned problems of the prior art. An object of the present invention is to provide means for realizing an appropriate viewfinder display according to the shooting situation.

  A camera according to a first aspect includes a focus detection unit, a finder, and a control unit. The focus detection unit detects a focus adjustment state of the photographing optical system. The viewfinder presents the subject image in the shooting screen to the user. In addition, the finder can switch between a first state in which the position display of the focus detection area in the shooting screen is superimposed on the subject image and a second state in which the display of the reference line for composition determination is superimposed on the subject image. . The control unit shifts the finder display state from the first state to the second state after the focus detection unit detects the in-focus state.

According to a second aspect, in the first aspect, the finder includes a finder optical system that guides the light flux from the subject that has passed through the photographing optical system to the user's eyes, and the position display of the focus detection area and the display of the reference line. A display element superimposed on the optical image of the system.
In a third aspect based on the first aspect, the camera further includes an imaging unit that captures a subject image based on the light beam that has passed through the photographing optical system. The finder includes a display unit that displays the position display of the focus detection area and displays the position display of the focus detection area and / or the display of the reference line so as to be superimposed on the output image of the imaging unit.

  In the present invention, the display superimposed on the subject image after the focus is switched from the display of the focus position to the display for determining the composition, and an appropriate finder display is performed according to the shooting situation.

(Description of the first embodiment)
FIG. 1 is a block diagram showing the configuration of the electronic camera of the first embodiment. FIG. 2 is a schematic diagram showing a photographing mechanism of the electronic camera of the first embodiment. In the first embodiment, an example of an electronic camera system in which a single-lens reflex type lens is replaceable will be described.
First, the photographing mechanism of the electronic camera will be described with reference to FIG. The electronic camera of this embodiment has a camera body 11 and a lens unit 12.

  Here, the camera body 11 and the lens unit 12 are each provided with a pair of mounts (not shown) having a male-female relationship. The lens unit 12 is connected to the camera body 11 in an exchangeable manner by coupling the above mounts with a bayonet mechanism or the like. Each of the mounts is provided with an electrical contact. When the camera body 11 and the lens unit 12 are connected, electrical connection between the two is established by contact between the electrical contacts.

The lens unit 12 includes a photographing optical system including a focusing lens 13. The focusing lens 13 is configured to be movable in the optical axis direction by a lens driving mechanism 14.
On the other hand, the camera body 11 includes a main mirror 15, a mechanical shutter 16, an image sensor 17, a sub mirror 18, a focus detection unit 19, and a finder optical system (20 to 24). The main mirror 15, the mechanical shutter 16, and the image sensor 17 are disposed along the optical axis of the photographing optical system. A sub mirror 18 is disposed behind the main mirror 15. A finder optical system is disposed on the upper part of the camera body 11. Further, a focus detection unit 19 is disposed below the camera body 11.

  The main mirror 15 is pivotally supported by a rotation shaft (not shown) and can be switched between an observation state and a retracted state. The main mirror 15 in the observation state is inclined and disposed in front of the mechanical shutter 16 and the image sensor 17. The main mirror 15 in the observation state reflects the light beam that has passed through the photographing optical system upward and guides it to the finder optical system. The central portion of the main mirror 15 is a half mirror. A part of the light beam transmitted through the main mirror 15 is refracted downward by the sub mirror 18 and guided to the focus detection unit 19. The focus detection unit 19 detects the image shift amount of the subject image divided by a separator lens (not shown) for each focus detection area, and performs so-called phase difference detection type focus detection.

Further, the retracted main mirror 15 is flipped upward together with the sub mirror 18 and is at a position off the photographing optical path. When the main mirror 15 is in the retracted state, the light beam that has passed through the photographing optical system is guided to the mechanical shutter 16 and the image sensor 17.
The viewfinder optical system includes a diffusing screen (focus plate) 20, a liquid crystal display element 21, a condenser lens 22, a pentaprism 23, and an eyepiece lens 24.

The diffusion screen 20 is located above the main mirror 15. The diffusion screen 20 is adjusted so as to form a surface optically equivalent to the imaging surface of the imaging element 17 with respect to the photographing optical system.
When the main mirror 15 is in the observation state, the light beam reflected by the main mirror 15 forms an image once on the diffusion screen 20. The light beam formed on the diffusing screen 20 passes through the liquid crystal display element 21, the condenser lens 22 and the pentaprism 23, and is guided to the exit surface having an angle of 90 ° with respect to the incident surface of the pentaprism 23. The light beam from the exit surface of the pentaprism 23 reaches the eyes of the user via the eyepiece lens 24.

  Here, the liquid crystal display element 21 displays various kinds of information on the optical image of the subject in a superimposed manner by selectively shielding an arbitrary region using a change in the refractive index of the liquid crystal. The liquid crystal display element 21 according to the first embodiment can switch between a first state and a second state where the light shielding portions are different. FIG. 3 shows a display in the first state of the liquid crystal display element 21. The liquid crystal display element 21 in the first state displays the position of the focus detection area (11 positions) and the range of the spot photometry area in the shooting screen. FIG. 4 shows the display of the liquid crystal display element 21 in the second state. The liquid crystal display element 21 in the second state displays a grid-like reference line for determining the composition.

  Hereinafter, the structure of the liquid crystal display element 21 of the first embodiment will be further described. The liquid crystal display element 21 is composed of a polymer dispersed liquid crystal panel using polymer dispersed liquid crystal. Here, the polymer dispersed liquid crystal includes known polymer network liquid crystal (PNLC) and polymer dispersed liquid crystal (PDLC). In this specification, a state in which a resin component in a liquid crystal solution containing a polymer dispersed liquid crystal is polymerized and cured is referred to as a polymer. In the following description, an example of a PN liquid crystal panel using a polymer network liquid crystal will be described for the sake of convenience, but a PD liquid crystal panel using a polymer dispersed liquid crystal may be used.

5 and 6 are schematic diagrams for explaining the operating principle of the liquid crystal display element 21. FIG. The liquid crystal display element 21 includes a pair of translucent substrates 31 and 32, transparent conductive films 33 and 34, and a polymer dispersed liquid crystal material 35.
The pair of translucent substrates 31 and 32 are arranged in a facing state with a predetermined gap therebetween. Each translucent board | substrate 31 and 32 is comprised, for example with glass. In addition, transparent conductive films 33 and 34 such as ITO are formed on the surfaces of the translucent substrates 31 and 32 facing each other.

A polymer-dispersed liquid crystal material 35 is sandwiched between the translucent substrates 31 and 32.
The polymer-dispersed liquid crystal material 35 is in a state where liquid crystal particles 37 are dispersed in a transparent polymer polymer 36. The polymer dispersed liquid crystal material 35 is sealed between the translucent substrates 31 and 32 by a liquid crystal sealing material (not shown).
The liquid crystal molecules 38 in the liquid crystal particles 37 have optical anisotropy. That is, the liquid crystal molecules 38 have two refractive indexes, an ordinary refractive index no corresponding to the major axis of the ellipsoid and an extraordinary refractive index ne corresponding to the minor axis of the ellipsoid. On the other hand, the polymer 36 is isotropic. Further, the refractive index np of the polymer 36 is set to be approximately equal to one of the ordinary refractive index no or the extraordinary refractive index ne of the liquid crystal molecules 38. As an example, liquid crystal molecules having an ordinary refractive index no of 1.45 to 1.55 and an extraordinary refractive index ne of 1.65 to 1.80 are used for the polymer dispersed liquid crystal material 35. Similarly, a polymer having a refractive index np of 1.45 to 1.55 is used for the polymer dispersed liquid crystal material 35. At this time, it is preferable to make np and no substantially equal (np≈no).

Further, in a state where no voltage is applied to the liquid crystal display element 21 (FIG. 5), the liquid crystal molecules 38 in the liquid crystal particles 37 are aligned in a random direction. In this case, scattering occurs due to the difference in refractive index between the polymer polymer 36 and the liquid crystal particles 37. Therefore, the liquid crystal display element 21 blocks the incident light flux.
On the other hand, in a state where a voltage is applied to the liquid crystal display element 21 (FIG. 6), an electric field in the vertical direction in the figure is generated and the liquid crystal molecules 38 are aligned in the electric field direction. Accordingly, since the refractive index of the liquid crystal molecules 38 during alignment becomes equal to the refractive index of the polymer polymer 36, the light beam incident on the liquid crystal display element 21 can pass through the liquid crystal display element 21 without being scattered.

FIG. 7 is a diagram for more specifically explaining an example of the configuration of the liquid crystal display element 21 in the first embodiment. In FIG. 7, configurations corresponding to those in FIGS. 5 and 6 are denoted by the same reference numerals, and redundant description is omitted.
A first electrode layer 39, an insulating layer 40, and a second electrode layer 41 are laminated in order from the bottom on the inner surface (lower surface side in the drawing) of the translucent substrate 31 located on the upper side in FIG. . The first electrode layer 39, the insulating layer 40, and the second electrode layer 41 are all translucent. On the other hand, on the transparent conductive film 34 on the translucent substrate 32 side, display pattern electrodes and source signal lines (not shown) as switching elements are formed.

  FIG. 8 is a perspective view for explaining the wiring state of the first electrode layer 39, the insulating layer 40, and the second electrode layer 41. On the first electrode layer 39, electrodes are formed in the shape of the display pattern. In FIG. 8, the first electrode layer 39 is formed with a spot photometry area display pattern and a focus detection area display pattern. The insulating layer 40 insulates the first electrode layer 39 and the second electrode layer 41 from each other. A wiring pattern for applying a voltage to the display pattern of the first electrode layer 39 is formed on the second electrode layer 41. Through holes are formed in the first electrode layer 39, the insulating layer 40, and the second electrode layer 41 at locations where the display pattern of the first electrode layer 39 and the wiring pattern of the second electrode layer 41 overlap. In the assembled state shown in FIG. 7, the through hole is filled with a light-transmitting conductive material 42, and the display pattern of the first electrode layer 39 and the wiring of the second electrode layer 41 are formed at the position of the through hole. Electrically connected. In the liquid crystal display element 21, if necessary, the electrode layer for display pattern, the insulating layer 40, and the electrode layer for wiring may be further increased to be multilayered (illustration of the multilayered layer is omitted).

  In the liquid crystal display element 21 of the first embodiment, since the wiring of the second electrode layer 41 is insulated from the first electrode layer 39, wiring can be performed across the display pattern. Therefore, it is not necessary to divide the display pattern for wiring to the electrodes, and the degree of freedom in layout of the display pattern is greatly improved. Further, in the above configuration, the portion of the wiring routed to the display pattern is lit, and the phenomenon of blocking the user's field of view in the finder does not occur.

  Next, returning to FIG. 1, the circuit configuration of the electronic camera will be described. In addition to the image sensor 17, the focus detector 19, and the liquid crystal display device 21, the camera body 11 includes an analog signal processor 51, a timing generator (TG) 52, a memory 53, an image processor 54, a recording I / O F55, a release button 56, a display driver 57, a CPU 58, and a bus 59 are provided. The memory 53, the image processing unit 54, the recording I / F 55, and the CPU 58 are connected via a bus 59.

The imaging element 17 is a sensor for generating a main image that is a recording image. The image sensor 17 photoelectrically converts the light beam that has passed through the lens unit 12 at the time of release and outputs an analog image signal of the main image. The output signal of the image sensor 17 is input to the analog signal processing unit 51.
The analog signal processing unit 51 is an analog front end circuit having a CDS circuit, a gain circuit, an A / D conversion circuit, and the like. The CDS circuit reduces the noise component of the output of the image sensor 17 by correlated double sampling. The gain circuit amplifies the gain of the input signal and outputs it. In this gain circuit, the imaging sensitivity corresponding to the ISO sensitivity can be adjusted. The A / D conversion circuit performs A / D conversion of the output signal of the image sensor 17. In FIG. 1, illustration of each circuit of the analog signal processing unit 51 is omitted.

The TG 52 supplies timing pulses to the image sensor 17 and the analog signal processing unit 51 based on instructions from the CPU 58. In the electronic camera, the charge accumulation time of the image sensor 17 and the signal reading timing are adjusted by the timing pulse of the TG 52.
The memory 53 is a buffer memory for temporarily recording image data in a pre-process or post-process of image processing by the image processing unit 54.

The image processing unit 54 performs various types of image processing (defective pixel correction, color interpolation, gradation conversion processing, white balance adjustment, edge enhancement, etc.) on the output signal of the analog signal processing unit 51 to generate the data of the main image Is generated. The image processing unit 54 also executes compression / decompression processing of the data of the main image.
A connector for connecting the recording medium 60 is formed in the recording I / F 55. The recording I / F 55 executes data writing / reading with respect to the recording medium 60 connected to the connector. The recording medium 60 is composed of a hard disk, a memory card incorporating a semiconductor memory, or the like. In FIG. 1, a memory card is illustrated as an example of the recording medium 60.

The release button 56 receives from the user an instruction input to start AF operation before shooting by a half-press operation and an instruction input to start exposure at the time of shooting by a full-press operation.
The display driver 57 controls the display of the liquid crystal display element 21 by applying a voltage to the electrodes of the liquid crystal display element 21 based on an instruction from the CPU 58.
The CPU 58 is a processor that performs overall control of each unit of the electronic camera. For example, the CPU 58 executes drive control for the main mirror 15 and the mechanical shutter 16.

  Further, the CPU 58 calculates the defocus amount (the shift amount and the shift direction from the in-focus position) of the focusing lens 13 for each focus detection area based on the image shift amount of the focus detection unit 19. Then, the CPU 58 performs AF control by operating the lens driving mechanism 14 via the mount. Further, the CPU 58 performs a known AE calculation based on the output of the photometry unit (not shown), and also plays a role of determining parameters (exposure time, aperture value, imaging sensitivity, etc.) of the photographing conditions of the main image.

The operation of the electronic camera in the first embodiment will be described below with reference to the flowchart of FIG.
Step 101: The CPU 58 sets the display state of the liquid crystal display element 21 to the first state (FIG. 3).
Further, at the stage of S101, the main mirror 15 is at the observation position. Therefore, the user can observe the optical image of the subject from the eyepiece lens 24 by the light beam that has passed through the lens unit 12. At this time, since the liquid crystal display element 21 is in the first state, the position of the focus detection area and the range of the spot photometry area in the shooting screen are superimposed and displayed on the optical image of the subject that can be observed from the viewfinder. .

Step 102: The CPU 58 determines whether or not the release button has been pressed halfway. If there is a half-press operation (YES side), the CPU 58 proceeds to S103. On the other hand, when there is no half-press operation (NO side), the CPU 58 waits for a half-press operation from the user.
Step 103: The CPU 58 executes AF of the lens unit 12 based on the output of the focus detection unit 19. At this time, the CPU 58 displays the position of the selected focus detection area for the user by means such as irradiating the diffusing screen 20 with illumination light.

Step 104: The CPU 58 determines whether or not focusing is successful in the AF operation of S103. If focusing is successful (YES side), the CPU 58 proceeds to S105. On the other hand, when focusing fails (NO side), the CPU 58 returns to S102 and repeats the above operation.
Step 105: The CPU 58 changes the display state of the liquid crystal display element 21 to the second state (FIG. 4). As a result, a grid-like reference line for determining the composition is superimposed on the optical image of the subject that can be observed from the viewfinder after focusing.

Step 106: The CPU 58 determines whether or not the release button 56 has been fully pressed. If there is a full press operation (YES side), the CPU 58 proceeds to S107. On the other hand, when there is no full pressing operation (NO side), the CPU 58 proceeds to S108.
Step 107: The CPU 58 executes a photographing process for the main image. At this time, the CPU 58 retracts the main mirror 15 from the photographing optical path and drives the image sensor 17 to photograph the main image. Thereafter, the image processing unit 54 generates image data of the main image, and the CPU 58 records the image data of the main image on the recording medium 60. This completes a series of shooting operations. Note that the CPU 58 may return to S101 after the shooting process of S107 and continue the shooting operation.

Step 108: The CPU 58 determines whether or not the half-pressed state of the release button 56 has been released. When the half-pressed state is released (YES side), the CPU 58 proceeds to S101. On the other hand, if the half-pressed state continues (NO side), the CPU 58 returns to S106. This is the end of the description of the flowchart of FIG.
Hereinafter, effects of the electronic camera of the first embodiment will be described. In the first embodiment, the position of the focus detection area is superimposed on the optical image of the finder before focusing (S101), and a grid-like reference line is superimposed on the optical image of the finder after focusing (S101). S105). Therefore, since the display of the finder is optimized before and after focusing, the user can smoothly shoot without being confused by complicated display.

(Description of Second Embodiment)
FIG. 10 is a block diagram illustrating a circuit configuration of the electronic camera according to the second embodiment. In the description of the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the duplicate description is omitted.
The second embodiment is a modification of the first embodiment, and a case of a compact electronic camera having no finder optical system will be described. An electronic camera 11 a shown in FIG. 10 includes a photographing optical system including a focusing lens 13 and a lens driving mechanism 14. A monitor 61 that functions as an electronic finder is connected to the CPU 58 via the bus 59 in the electronic camera 11a. Since the electronic camera 11a does not have an optical finder, it is different from the electronic camera of the first embodiment in that the liquid crystal display element 21 and the display driver 57 are not provided.

The image sensor 17 according to the second embodiment outputs a through image by thinning-out readout at predetermined intervals during shooting standby (non-release). The image signal of the through image is used for various arithmetic processes by the CPU 58 and display on the monitor 61.
The CPU 58 executes a known contrast detection AF based on the through image data. Further, the CPU 58 executes an exposure calculation based on the data of the through image. Further, the CPU 58 performs control related to display on the monitor 61.

The monitor 61 displays a screen instructed by the CPU 58. For example, a display image (view image) based on a through image can be displayed as a moving image on the monitor 61 during the above-described shooting standby. At this time, various information necessary for photographing can be superimposed on the view image on the monitor 61 by an on-screen function.
Therefore, the CPU 58 according to the second embodiment can superimpose the focus detection area display similar to FIG. 3 and the grid-like reference line display similar to FIG. 4 on the view image on the monitor 61. According to the configuration of the second embodiment, substantially the same effect as that of the first embodiment can be obtained.

(Supplementary items of the embodiment)
(1) In the first embodiment, the configuration of the finder of the single-lens reflex type electronic camera has been described. However, the finder of the first embodiment is also applied to a silver halide camera that takes a subject image with a film and shoots the main image. can do.
(2) In the above-described embodiment, the CPU 58 may further display a horizontal reference line superimposed on the display in the first state before focusing. Further, in the above embodiment, when performing continuous AF, the CPU 58 may alternately switch the display of the first state and the display of the second state.

(3) In the above embodiment, when the manual focusing is performed, the CPU 58 may always perform the reference line display in the second state. Further, in a camera with interchangeable lenses, when the lens information cannot be acquired from the lens unit 12, the CPU 58 may not display the position of the focus detection area.
It should be noted that the present invention can be implemented in various other forms without departing from the spirit or main features thereof. For this reason, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The present invention is defined by the claims, and the present invention is not limited to the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

The block diagram which shows the structure of the electronic camera of 1st Embodiment. Schematic diagram showing the photographing mechanism of the electronic camera of the first embodiment The figure which shows the display in a 1st state of a liquid crystal display element The figure which shows the display in a 2nd state of a liquid crystal display element Schematic diagram explaining the operating principle of liquid crystal display elements Schematic diagram explaining the operating principle of liquid crystal display elements The figure explaining an example of a structure of the liquid crystal display element in 1st Embodiment. Explanatory drawing of the wiring state of a 1st electrode layer, an insulating layer, and a 2nd electrode layer Flowchart for explaining the operation of the electronic camera in the first embodiment The block diagram which shows the structure of the electronic camera of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Camera body, 11a ... Electronic camera, 13 ... Focusing lens, 15 ... Main mirror, 17 ... Imaging element, 19 ... Focus detection part, 20 ... Diffusing screen (focus plate), 21 ... Liquid crystal display element, 22 ... Condenser lens , 23 ... Penta prism, 24 ... Eyepiece, 57 ... Display driver, 58 ... CPU, 61 ... Monitor

Claims (3)

A focus detection unit for detecting a focus adjustment state of the photographing optical system;
The subject image in the shooting screen is presented to the user, and the first state in which the focus detection area position display in the shooting screen is superimposed on the subject image and the reference line for composition determination are displayed on the subject image. A finder capable of switching between the second states to be superimposed;
A control unit that shifts the display state of the finder from the first state to the second state after the focus detection unit detects the in-focus state;
A camera comprising: The camera of claim 1,
The finder superimposes a finder optical system that guides a light beam from a subject that has passed through the photographing optical system to a user's eyes, a position display of the focus detection area, and a display of the reference line on an optical image of the finder optical system. And a display element. The camera of claim 1,
An imaging unit that captures the subject image based on the light beam that has passed through the imaging optical system;
The camera includes a display unit that displays at least one of a position display of the focus detection area and a display of the reference line superimposed on an output image of the imaging unit.

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