JP2007311925A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the thickness of a digital camera provided with an electronic viewfinder employing a reflection type display element. <P>SOLUTION: An illumination LED 40 for irradiating a display surface 46 of the reflection type display element 44 with a light, an illumination mirror 41 for guiding the light emitted from the illumination LED 40 to the display surface 46, and a diffusion polarizing filter 42, are arranged in a direction of an eyepiece window 25 provided on the back surface of the digital camera for the reflection type display element 44. The illumination LED 40, the illumination mirror 41 and the diffusion polarizing filter 42 are also arranged on the substantial lower part of a finder optical axis S2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an imaging apparatus including an electronic viewfinder, and more particularly to an imaging apparatus using a reflective display element as a display element of an electronic viewfinder.

  Digital cameras that are widely used now include a liquid crystal panel that displays and displays captured images and functions as a viewfinder during shooting. However, since the liquid crystal panel has poor visibility in a bright place and there is a demand from users who can take pictures with a silver halide camera, a digital camera equipped with a viewfinder is also on the market.

  Many digital cameras in recent years have a high-magnification photographing lens, and when an optical viewfinder is used for such a digital camera, parallax becomes a problem. Further, if the optical system of the optical viewfinder is configured so as to eliminate parallax, there is a problem that the entire length of the optical system becomes long and the digital camera becomes large. Therefore, electronic viewfinders are often used in current digital cameras.

  An electronic viewfinder is composed of a display element for displaying a subject image and an eyepiece for magnifying and observing the image of the display element, and the finder optical axis is generally arranged parallel to the photographing optical axis. Is. However, the compact digital camera has a problem that it cannot be thinned due to the length of the finder optical axis. Therefore, in the inventions described in Patent Documents 1 and 2, the optical path length in the thickness direction of the digital camera is reduced by arranging a reflection mirror between the display element and the eyepiece lens and bending the finder optical axis. It is shortened.

Conventionally, a transmissive liquid crystal panel illuminated from the back has been used as a display element of an electronic viewfinder. However, this transmissive liquid crystal panel has the disadvantages that the screen is dark and the response is slow. Therefore, an electronic viewfinder using a reflective display element such as LCOS (Liquid Crystal On Silicon) or DMD (Digital Mirror Device) has been invented (for example, see Patent Document 3).
JP 2003-174573 A Japanese Laid-Open Patent Publication No. 2003-161993 JP 2003-153044 PR

  In order to use a reflective display element, an illumination element and an illumination optical system that irradiates the display surface of the reflective display element with light emitted from the illumination element are required. Therefore, there is a problem that the digital camera cannot be thinned depending on the arrangement of the illumination element and the illumination optical system. For example, in the invention described in Patent Document 3, the display surface of the reflective display element is disposed so as to face upward, and the displayed image is reflected by the reflection mirror and incident on the eyepiece provided on the back surface of the camera body. However, since the illumination element and the illumination optical system are arranged on the front side of the camera body relative to the reflective display element, the length of the electronic viewfinder in the thickness direction of the camera body Lengthen up and hinder the thinning of digital cameras.

  An object of the present invention is to reduce the thickness of a digital camera including an electronic viewfinder using a reflective display element.

  An imaging apparatus according to the present invention is provided on the back surface of the apparatus main body, and reflects an eyepiece used for observing a subject image and light irradiated on a display surface in a direction intersecting a finder optical axis of the eyepiece. Reflective display means for forming a subject image, a reflective mirror for reflecting the subject image formed by the reflective display means and entering the finder optical axis, and the eyepiece portion with respect to the reflective display means And illuminating means for irradiating the display surface with light.

  Further, the reflection type display means is arranged so that a display surface faces upward, and the illumination means is arranged substantially below a finder optical axis formed by the reflection mirror and the eyepiece. It is characterized by being.

  Further, the illuminating means includes a light source unit having a light emitting surface arranged in parallel with the display surface, and an illumination optical system that guides light emitted from the light source unit toward the display surface. .

  The illumination unit includes a light source unit disposed so that a light emitting surface is substantially orthogonal to the display surface, and an illumination optical system that guides light emitted from the light source unit toward the display surface. It is characterized by that.

  In the imaging apparatus of the present invention, the illuminating means for illuminating the display surface of the reflective display means is arranged on the eyepiece side with respect to the reflective display means. Compared with the case where it is arranged on the opposite side, the imaging device can be made thinner by the amount corresponding to the space for installing the illumination means itself.

  In addition, since the light source unit that configures the illumination unit and has the light emitting surface is disposed so that the light emitting surface is substantially orthogonal to the display surface, the imaging device is further compared with the case where the light emitting surface is disposed substantially parallel to the display surface. Thinner.

  As shown in FIGS. 1 and 2, a digital camera 5 (imaging device) embodying the present invention is provided with a lens barrel 12 that holds an imaging lens on the front surface of the camera body 6 (device main body). Yes. On the upper surface of the camera body 6, a power button 16, a release button 17, and a mode switching dial 18 are provided. The power button 16 is used when the digital camera 5 is turned on or off. The release button 17 can be operated in two stages, half-press and full-press. When half-pressed, shooting preparation operations such as automatic exposure adjustment (AE) and automatic focus adjustment (AF) are performed, and an image is recorded when fully pressed.

  The mode switching dial 18 switches the operation mode of the digital camera 5. This operation mode includes a shooting mode in which a subject image is shot and the shot image is recorded on a recording medium such as a memory card 19 (see FIG. 5), a playback mode in which recorded image data is read out and displayed on the LCD 22, and various types of modes. There are setting modes for setting.

  As shown in FIG. 2, an operation unit 21, an LCD 22, an eyepiece window 25, an eyepiece 26, a finder switching button 27, and the like are provided on the back of the camera body 6. The operation unit 21 includes a zoom button 31, a menu button 32, a cross key 33, and the like.

  By operating the zoom button 31, a zoom lens 52, which will be described later, is moved to the close side or the infinity side. The menu button 32 is operated when displaying a menu screen on the LCD 22 or determining a selection content. The cross key 33 is operated when moving the cursor in the menu screen or the like. The LCD 22 not only displays an image in the playback mode and a menu in the setting mode, but also functions as an electronic viewfinder by displaying a through image in the shooting mode.

  The eyepiece window 25 (eyepiece part) constitutes a part of a reflection display finder 35 described later, and is surrounded by an eyepiece 26. The eyepiece 26 is provided so as to protrude from the back surface of the camera body 6, and the eyepiece 26 is looked into the eyepiece window 25 so as to press the periphery of the eye portion, and framing is performed while confirming the through image.

  The viewfinder switching button 27 is a switch for selecting either the LCD 22 or a reflection display finder 35 described later as an electronic viewfinder. Each time the finder switching button 27 is operated, the through image display is alternately switched between the LCD 22 and the reflective display finder 35.

  As shown in FIGS. 3 and 4, the digital camera 5 includes a reflective display finder 35. The reflection display finder 35 includes a reflection display unit 36, a reflection mirror 37, an eyepiece lens 38, and the above-described eyepiece window 25.

  The reflective display unit 36 includes a printed wiring board 39, an illumination LED 40 (illuminating unit, light source unit), an illumination mirror 41 (illuminating unit, illumination optical system), and a diffused polarization filter 42 (illumination) mounted on the printed wiring board 39. Means, illumination optical system), a polarizing beam splitter 43 (illumination means, illumination optical system), and a reflective display element 44 (reflection type display means). The printed wiring board 39 is connected to a printed wiring board (not shown) constituting the digital camera 5.

  The illumination LED 40 is composed of LEDs of three colors of blinking red (R), green (G), and blue (B), and forms a light emitting surface 45. Since the light emitting surface 45 is installed in a direction substantially parallel to the display surface 46 to be described later, the light of the three colors R, G, and B emitted from the light emitting surface 45 is reflected directly or by the illumination mirror 41. The light enters the diffusing polarizing filter 42. The illumination LED 40 is disposed on the eyepiece window 25 side with respect to the reflective display unit 36.

  The diffusion polarizing filter 42 diffuses the light emitted from the light emitting surface 45, adjusts it to S-polarized light, and transmits it to the reflective display element 44 side. Since the polarization beam splitter 43 transmits only P-polarized light and reflects S-polarized light, the diffused three colors of S-polarized light are reflected directly or reflected by the polarization beam splitter 43 and enter the reflective display element 44.

  The reflective display element 44 is made of, for example, an LCOS (Liquid Crystal On Silicon) element. As is well known, the LCOS element has a plurality of pixel electrodes made of a glossy metal such as aluminum in order to reflect light. Each pixel electrode is turned on and off by an FET (Field Effect Transistor) formed under the pixel electrode and corresponding to each pixel electrode to control the orientation of the liquid crystal material disposed above the pixel electrode.

  The light incident on the pixel electrode controlled to be on is reflected as P-polarized light by the liquid crystal material above the pixel electrode, and the light incident on the pixel electrode controlled to be off is Reflected in the polarization state. The reflective display element 44 of the digital camera 5 uses a ferroelectric liquid crystal material as a liquid crystal material in order to improve response performance.

  In addition, a surface that includes a plurality of pixel electrodes and reflects light is used as a display surface 46 of the reflective display unit 36. The display surface 46 is arranged substantially parallel to the photographing optical axis S1 of the imaging lens 11, and displays a through image by reflecting light in a direction intersecting the finder optical axis S2.

  The reflection mirror 37 receives and reflects the through image displayed on the display surface 46 as described above, bends it to the viewfinder optical axis S2, and guides it to the eyepiece 38. The through image magnified by the eyepiece lens 38 is observed through the eyepiece window 25 as described above.

  As shown in FIG. 5, the digital camera 5 is detachably provided with a memory card 19 that is an external memory for storing captured image data. The CPU 51 comprehensively controls the entire digital camera 5 based on operation instructions input from the power button 16, the release button 17, the mode switching dial 18, and the operation unit 21.

  The imaging lens 11 includes, for example, a zoom lens 52, a diaphragm 53, and a focus lens 54. The diaphragm 53 adjusts the amount of photographing light by changing the aperture area of the diaphragm. The zoom lens 52 and the focus lens 54 are movably provided along the photographing optical axis S1, and perform zooming and focus adjustment, respectively. The zoom lens 52 moves according to the operation of the zoom button 31 and changes the zoom magnification. The focus lens 54 moves to the near side or the infinity side as the zoom lens 52 is zoomed or the release button 17 is half-pressed to adjust the focus. The diaphragm 53 operates when the release button 17 is half-pressed, and adjusts the amount of photographing light. These are driven by a lens motor 56. The lens motor 56 is controlled by a motor driver 57 connected to the CPU 51.

  Behind the imaging lens 11 is a CCD 61 that captures a subject image that has passed through the imaging lens 11. The CCD 61 is driven by a CCD driver 62 controlled by the CPU 51. The analog imaging signal output from the CCD 61 is input to a correlated double sampling circuit (CDS) 66 to remove noise and is amplified by an amplifier (AMP) 67. Then, it is converted into digital image data by an A / D converter (A / D) 68. The image data output from the A / D 68 is input to a DSP (Digital Signal Processor) 69 as R, G, B image data that accurately corresponds to the amount of charge stored in each cell of the CCD 61.

  The DSP 69 includes an image input controller 71, an image quality correction processing circuit 72, a YC conversion processing circuit 73, and a compression / decompression processing circuit 74. The DSP 69 temporarily records the image data in the SDRAM 81 and performs various image processing. The image input controller 71 buffers the image data input from the A / D 68 and writes the image data to the SDRAM 81 connected via the data bus 76. The SDRAM 81 is a working memory, and is loaded with image data and a control program executed by the CPU 51. The EEPROM 82 stores the control program and setting information.

  Further, via the data bus 76, it is detected whether or not the exposure amount, that is, the shutter speed of the electronic shutter and the aperture value of the aperture 53 is appropriate for shooting, and whether or not the white balance is appropriate for shooting. An AWB detection circuit (not shown) is connected to an AF detection circuit (not shown) that detects whether or not the focus adjustment of the imaging lens 11 is appropriate for shooting. The CPU 51 controls the imaging lens 11 based on these detection results.

  The image quality correction processing circuit 72 reads the image data from the SDRAM 81, performs various image correction processes such as gradation conversion, white balance correction, and γ correction process, and records the image data in the SDRAM 81 again. The YC conversion processing circuit 73 reads the image data processed by the image quality correction processing circuit 72 from the SDRAM 81 and converts it into a luminance signal Y and color difference signals Cr and Cb. The compression / decompression processing circuit 74 compresses the YC-converted image data by, for example, a predetermined method and outputs it in a predetermined file format such as TIFF or JPEG. The compressed image data is recorded on the memory card 19 via the media controller 86.

  When the release button 17 is pressed, the CCD 61 outputs main image data having a large number of pixels and also outputs a through image having a small number of pixels for through display. The through image is output at a frame rate of 30 frames per second while the through display is turned on, and the through image output from the CCD 61 is temporarily recorded in the SDRAM 81 in the same manner as the main image data. The main image data is recorded on the memory card 19 after being subjected to the above-described various image processing, whereas the through image data is read from the SDRAM 81 and displayed on the LCD 22 or the reflection display finder 35. In the SDRAM 81, a VRAM area for storing a through image is secured, and the through image in the VRAM area is updated at any time according to the frame rate.

  When the LCD 22 is selected as the electronic viewfinder, the through image data is converted into an analog composite signal by the encoder 87 and video output to the LCD 22. On the other hand, when the reflective display finder 35 is selected as the electronic viewfinder, the reflective display controller 89 switches on and off the pixel electrodes of the reflective display element 44 based on the input through image data. The timing at which each LED of the illumination LED 40 blinks is controlled.

  Hereinafter, the operation of the digital camera 5 configured as described above will be described. In order to perform shooting using the digital camera 5, after turning on the power, the mode switching dial 18 and the menu button 32 are operated to select an appropriate shooting mode.

  When the finder switching button 27 is operated to enable the reflective display finder 35, the reflective display controller 89 controls each pixel of the reflective display element 44 based on the through image data, and switches on and off. At the same time, the reflective display controller 89 controls the illumination LED 40 to flash the light of the three colors R, G, and B in order.

  These lights emitted from the light emitting surface 45 are reflected directly or to the illumination mirror 41, diffused by the diffusion polarizing filter 42, adjusted to S-polarized light, and transmitted to the reflective display element 44 side. At this time, the reflective display controller 89 controls each pixel electrode of the reflective display element 44 on the basis of the through image data, and switches on and off. Then, the diffused S-polarized light of the three colors is incident on the display surface 46 directly or after being reflected by the polarization beam splitter 43.

  The light reflected by the pixel electrode controlled to be off remains S-polarized light and cannot pass through the polarization beam splitter 43. On the other hand, since the light reflected by the pixel electrode controlled to be on is adjusted to P-polarized light, the light passes through the polarization beam splitter 43, is reflected by the reflection mirror 37, is bent in the direction of the finder optical axis S2, and is the eyepiece 38. Led to.

  By observing this through the eyepiece window 25, framing is performed, and when the composition is determined, the release button 17 is operated to record the subject image on the memory card 19.

  As described above, the digital camera 5 of the present embodiment uses the reflective display element 44 in the electronic viewfinder, and the illumination LED 40 that irradiates the reflective display element 44 with the light LED 40 with respect to the reflective display element 44. Place on the side. Therefore, in the digital camera 5 of the present embodiment, the camera body 6 can be made thinner than when the illumination LED 40 is disposed on the imaging lens 11 side with respect to the reflective display element 44. Since the illumination LED 40 is disposed below the finder optical axis S2, the reflective display finder 35 can be mounted on the digital camera in a space-saving manner.

  In the above-described first embodiment, the illumination LED 40 is installed so that the light emitting surface 45 and the display surface 46 are substantially parallel to each other. The example which installs illumination LED so that a light emission surface is substantially orthogonal is shown. The description of the same parts as those in the first embodiment is omitted.

  As shown in FIGS. 6 and 7, the illumination LED 240 of the reflective display unit 236 that constitutes the reflective display finder 235 of the digital camera 205 is installed such that the light emitting surface 245 is substantially orthogonal to the display surface 46. Yes. Therefore, the light emitted from the light emitting surface 245 is directly incident on the diffusion polarizing filter 42.

  By installing the illumination LED 40 in this way, the reflective display unit 236 can be further mounted on the digital camera in a space-saving manner. Furthermore, since the illumination mirror 41 required in the first embodiment is not necessary, the number of parts can be reduced.

  In the first embodiment and the second embodiment, the LED is used as the illumination element of the reflective display unit 36. However, the present invention is not limited to this, and it is necessary to use light sources of three colors R, G, and B. Nor. For example, a light source that is not an LED may be used. Further, for example, R, G, and B may be realized by a rotating color filter or the like using an LED that realizes white light.

  In the first embodiment and the second embodiment, LCOS elements using ferroelectric liquid crystals are used. However, the present invention is not limited to this. For example, a reflective display element such as a DMD (Digital Mirror Device) is used. Also good.

  In the first embodiment and the second embodiment, the reflection mirror 37 is used. However, the present invention is not limited to this. For example, a prism or the like may be used.

  In the above-described embodiment, an example of a digital camera that captures a still image has been described. However, the present invention is not limited to this, and imaging that includes an electronic viewfinder that uses a reflective display element such as a digital video camera that captures moving images. The present invention can be applied to an apparatus.

It is a perspective view which shows the external appearance of the digital camera which implemented this invention. It is a rear view of the digital camera which implemented this invention. It is sectional drawing which shows arrangement | positioning of the main structures of the digital camera which implemented this invention. It is sectional drawing which shows the structure of a reflective display finder. It is a block diagram showing the electric constitution of the digital camera which implemented this invention. It is sectional drawing which shows arrangement | positioning of the main structures of the digital camera of 2nd Embodiment. It is sectional drawing which shows the structure of the reflective display finder of 2nd Embodiment.

Explanation of symbols

5,205 Digital camera 6 Camera body (device main body)
25 Eyepiece window (eyepiece)
26 Eyepiece 27 Viewfinder switching button 35, 235 Reflective display finder 36, 236 Reflective display unit 37 Reflective mirror 38 Eyepiece 40, 240 Illumination LED (illumination means, light source)
41 Illumination mirror (illumination means, illumination optical system)
42 Diffuse polarizing filter (illumination means, illumination optical system)
43 Polarizing beam splitter (illumination means, illumination optical system)
44 reflective display elements (reflective display elements)
45,245 Light emitting surface 46 Display surface S1 Shooting optical axis S2 Viewfinder optical axis 84 Reflective display controller

Claims (4)

An eyepiece provided on the back of the apparatus body and used to observe the subject image;
Reflective display means for reflecting the light irradiated on the display surface in a direction intersecting the finder optical axis of the eyepiece to form a subject image;
A reflection mirror that reflects the subject image formed by the reflective display means and enters the finder optical axis;
An imaging apparatus comprising: an illuminating unit that is disposed on the eyepiece side with respect to the reflective display unit, and irradiates light on the display surface. The reflective display means is arranged so that a display surface faces upward, and the illumination means is arranged substantially below a finder optical axis formed by the reflective mirror and the eyepiece. The imaging apparatus according to claim 1. The illumination means includes a light source unit having a light emitting surface arranged in parallel with the display surface;
The imaging apparatus according to claim 1, further comprising an illumination optical system that guides light emitted from the light source unit toward the display surface. The illumination means includes a light source unit disposed so that a light emitting surface is substantially orthogonal to the display surface;
The imaging apparatus according to claim 1, further comprising an illumination optical system that guides light emitted from the light source unit toward the display surface.

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