JP4544207B2 - Display device and camera - Google Patents

Description

The present invention relates to a beauty camera Oyo display device.

  Conventionally, for example, a display device as disclosed in Patent Document 1 is known as an in-finder display device of a camera. In the display device, a display unit provided on a display plate is illuminated with an LED, and illumination light reflected by the display unit is observed through an eyepiece optical system.

JP 2001-281852 A

  However, in the above-described conventional apparatus, it is necessary to provide LEDs as many as the number of display units provided on the display plate, and there is a problem that the illumination optical system becomes larger as the number of display units increases.

According to a first aspect of the present invention, there is provided a camera comprising: a focusing screen on which a subject image is formed by a shooting lens; a display plate disposed in proximity to the focusing plate in an optical path of transmitted light that has passed through the shooting lens; An observation optical system for observing the image of the subject formed through the display plate, a light source for emitting an illumination beam, and the incident illumination beam as a plurality of reproduction beams through one diffraction grating. A hologram that exits in different directions, a light shielding element that is disposed in the optical path of each of the plurality of reproduction light beams, and that individually transmits or blocks each of the plurality of reproduction light beams, and a reproduction light beam that is transmitted through the light shielding elements And an optical system that makes the display plate incident on the display plate, the display plate having a reflecting portion that reflects the reproduction light beam incident on the display optical system to the observation optical system, and the observation optical system includes the focusing plate It said object image formed, characterized by observing the reproduction light beam reflected by the reflective portion.
According to a fifth aspect of the present invention, there is provided a display device comprising: a light source that emits an illumination light beam; a hologram that emits the incident illumination light beam as a plurality of reproduction light beams through a single diffraction grating in mutually different directions; A light-blocking element disposed in each optical path of the light beam and individually transmitting or blocking each of the plurality of reproduction light beams, and displaying a hologram reproduction image by the reproduction light beam transmitted through the light-shielding element. And

According to the present invention, to emit the reproduction light beam of multiple using hologram, because to perform display by using their reproduction light beam selectively, it is possible to reduce the size of the display device .

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a diagram for explaining an embodiment of a display device according to the present invention, in which the display device is applied to a display device in a viewfinder of a camera. FIG. 1 shows an example of a single-lens reflex camera. A lens barrel 3 having a photographing lens 2 is attached to a camera body 1.

Reference numeral 4 denotes an image pickup device for picking up a subject image formed by the photographing lens 2, and a CCD device or a silver salt film is used. A main mirror 5 is provided in front of the image sensor 4. FIG. 1 shows a non-exposure state, and the main mirror 5 is arranged on the optical axis. At the time of exposure, the main mirror 5 moves to a retracted position outside the optical path, and a subject image is projected onto the image sensor 4.

  At the time of non-exposure shown in FIG. 1, subject light from the photographic lens 2 is reflected by the main mirror 5 and forms an image on a focusing screen 6 provided at a position optically equivalent to the imaging surface of the imaging device 4. . The subject image formed on the focusing screen 6 is observed through the display plate 7, the pentaprism 8 and the eyepiece 9.

  The camera according to the present embodiment includes a light source 11, a hologram element 12, a light shielding element 13, and a projection optical system 10 as an in-finder display device. The projection optical system 10 is provided with lenses 100 and 101. The lens 101 has a lens surface and a reflection surface that reflects light from the lens 100 toward the pentaprism 8. As the light source 11, a semiconductor laser is used as a light source having a large light emission amount.

  A plurality of display lights emitted from the projection optical system 10 to the pentaprism 8 pass through the pentaprism 8 and enter a display plate 7 provided in the vicinity of the upper portion of the focusing screen 6. A display unit 70 is formed on the display plate 7 by a microprism, and the display light is reflected by the microprism of the display unit 70 toward the pentaprism 8 and is observed through the eyepiece 9. That is, the display is observed while being superimposed on the subject image.

[Description of display device in viewfinder]
FIG. 2 is a diagram illustrating generation of display light by the in-finder display device. When the hologram element 12 is irradiated with the laser light emitted from the light source 11, the laser light is diffracted by the hologram element 12, and a plurality of reproduction lights (diffracted lights) L1 to L5 are emitted. The hologram element 12 of the present embodiment is called a computer generated hologram (Computer Generated Hologram). Here, a hologram (diffraction grating) in which five dispersed lights having a rectangular cross section are emitted as reproduction lights L1 to L5. ) Is formed.

  Usually, an interference fringe is formed by object light and reference light by laser two-beam interference, and a hologram is formed by recording the interference fringe on a recording material. Object information is recorded on the hologram in the form of interference fringes, and when reproduction illumination light is irradiated onto the hologram, reproduction light having the same wavefront as the object light is emitted from the hologram. The computer generated hologram is obtained by calculating this interference fringe and recording it on a recording material. Therefore, in the computer generated hologram, an object for creating interference fringes does not have to exist, and a three-dimensional image of an imaginary object can be obtained.

  The reproduction lights L <b> 1 to L <b> 5 emitted from the hologram element 12 enter the light shielding element 13. Light shielding portions 131 to 135 are formed in regions where the reproduction lights L1 to L5 of the light shielding element 13 are incident. The light shielding units 131 to 135 can be switched between a transmission state and a non-transmission state, and in the example illustrated in FIG. 2, all the light shielding units 131 to 135 are in the transmission state. The reproduction lights L1 to L5 that have passed through the light shielding portions 131 to 135 are incident on the display portions 70 of the display panel 7. As will be described later, the display unit 70 is formed with a display pattern using microprisms. Here, as an example, five display patterns for displaying the autofocus area are formed.

  FIG. 3 is a cross-sectional view of the vicinity of the display unit 70 of the display panel 7. The display plate 7 is formed of a transparent member such as acrylic, and the portion other than the display unit 70 is a smooth parallel plate. The subject light F from the focusing screen 6 that passes through the parallel flat plate portion passes upward without being affected by anything, and is observed through the pentaprism 8 and the eyepiece 9.

  On the other hand, in the display unit 70, the region where the microprism 700 is provided is formed in the same shape as the autofocus area mark as shown in FIG. A display unit 70 is formed in each irradiation region of the reproduction lights L1 to L5 on the display board 7. When the reproduction light L2 having a rectangular cross section is irradiated on the area including the display unit 70 of the display plate 7, the reproduction light L2 incident on the display unit 70 is reflected twice by the reflection surface of the microprism 700 as shown in FIG. And emitted in the direction of the eyepiece. As a result, an autofocus area mark having the same shape as the display unit 70 is observed through the eyepiece 9. The same applies to the other reproduction lights L1, L3 to L5.

  Since the subject light F is refracted by the microprism 700, when the reproduction lights L1 to L5 are not incident on the display unit 70, the display unit 70 is compared with a parallel plate portion where the microprism 700 is not formed. It will be observed slightly dark.

  As described above, in the computer generated hologram, wavefronts corresponding to various shapes of marks can be easily formed as reproduction light, not limited to the autofocus area mark. Therefore, instead of forming dispersed light having a rectangular cross section as shown in FIG. 2, it is also possible to form reproduced light having the same shape as the display unit 70 shown in FIG. In this case, since the reproduction light has the same shape as the autofocus area mark, the shape of the region where the micro prism 700 is formed may not be the same shape as the autofocus area mark.

  Next, the light shielding element 13 will be described. As described above, the light shielding portions 131 to 135 of the light shielding element 13 can independently switch between the transmissive state and the non-transmissive state. Therefore, as shown in FIG. 4, by setting the light shielding portions 132 and 134 to the transmissive state and the light shielding portions 131, 133 and 135 to the non-transmissive state, only the reproduction lights L2 and L4 can be selectively transmitted. As a result, only the autofocus area mark by the reproduction lights L2 and L4 is observed through the eyepiece. In the example illustrated in FIG. 4, the hologram element 12 forms the reproduction lights L1 to L5 that reproduce the reproduction image having the same shape as the autofocus area mark. In the display plate 7 of FIG. 4, the display unit 70 that is a region where the microprism 700 is formed is not shown.

  As such a light shielding element 13, a polymer network liquid crystal element, a liquid crystal hologram element, a guest host liquid crystal element, an electrochromic element, or the like, or a mechanical shutter mechanism can be used.

  When a polymer network liquid crystal element is used as the light shielding element 13, a transparent electrode is provided in the region of the light shielding parts 131 to 135 in a liquid crystal substrate in which the polymer network liquid crystal is sandwiched between a pair of glass substrates. In the polymer network liquid crystal, the liquid crystal exists in a three-dimensional network structure of the polymer, and when no voltage is applied to the transparent electrodes of the light shielding portions 131 to 135, the liquid crystal molecules are aligned along the interface of the network structure. ing. Therefore, the liquid crystal causes strong scattering with respect to the incident reproduction light, and the reproduction light is hardly transmitted, and the light shielding portions 131 to 135 are in a non-transmission state. In addition, since the transparent electrode is not provided in areas other than the light shielding parts 131 to 135, the area is always in an opaque state.

  On the other hand, when a voltage is applied to the transparent electrodes of the light shielding parts 131 to 135, the liquid crystal molecules of the light shielding parts 131 to 135 are aligned in the direction perpendicular to the substrate by an electric field. As a result, the incident reproduction light is transmitted without being scattered, and the light shielding portions 131 to 135 are in a transmission state. By independently controlling the applied voltage of the transparent electrode provided in each of the light shielding parts 131 to 135, each transmission / non-transmission state can be individually controlled.

  The guest host liquid crystal element and the electrochromic element can be used in the same manner as the polymer network liquid crystal element. In the case of a guest-host liquid crystal element, when a dye having anisotropy in light absorption in the major axis direction and the minor axis direction of a molecule is melted in a liquid crystal having a fixed molecular arrangement, the dye molecules are arranged in parallel with the liquid crystal molecules. And a transparent state and a coloring state can be switched according to voltage application / non-application. In an electrochromic device, a chromic substance undergoes a redox reaction by an external electrical stimulus, and the color of the chromic substance changes reversibly.

  The liquid crystal hologram element is a liquid crystal plate on which interference fringes are formed by a liquid crystal layer and a polymer layer. The orientation of the anisotropic liquid crystal molecules contained in the liquid crystal layer is random when no voltage is applied, and the portion where the interference fringes are formed functions as a diffraction grating for incident light. On the other hand, when a voltage is applied, the liquid crystal molecules are aligned in the direction perpendicular to the substrate, and the diffraction function of the interference fringes disappears to become transparent. As a function of the diffraction grating, a light scattering function and a lens function can be provided. When the light scattering function is provided, the incident light is scattered and impermeable when no voltage is applied, and becomes transparent and transmissive when voltage is applied.

  By the way, as shown in FIG. 2, when a plurality of reproduction lights are generated by the hologram element 12, the reproduction light tends to spread as it progresses, so that the lens 100 is inserted to suppress the spread. Therefore, when a liquid crystal hologram element is used for the light shielding plate 13, the lens function of the lens 100 can be given to the light shielding plate 13, and the lens 100 can be omitted. For example, two liquid crystal hologram elements are stacked, one functioning as a shutter and the other functioning as a lens. In the case of the other hologram element, it functions as a lens when no voltage is applied.

  When producing a hologram element having a lens function, first, a liquid crystal and a photocurable monomer are mixed and the liquid crystal is dispersed in the monomer. Then, a liquid crystal cell sandwiching the mixed material is made. A light beam emitted from a point light source and the reference light are caused to interfere with each other to form bright and dark interference fringes, and a liquid crystal cell is disposed in the interference fringes. In the interference fringe bright portion, the monomer is cured to become a polymer, and that portion becomes a refractive index isotropic region. Most of the liquid crystal in the interference fringe bright portion is pushed out of the interference fringe bright portion during the curing and moves to the interference fringe dark portion. The interference fringe dark portion is a refractive index anisotropy region substantially composed of liquid crystal. As a result, interference fringes (diffraction gratings) due to the refractive index isotropic region and the refractive index anisotropic region are formed in the liquid crystal layer, and a hologram element having a lens function is formed.

  FIG. 5 shows a configuration in which a hollow pentamirror 18 is used in place of the pentaprism 8 of FIG. Reference numeral 30 denotes a display optical system, which is provided with the light source 11, the hologram element 12, the light shielding element 13, and the lenses 100 and 101 shown in FIG. The reproduction light L emitted from the display optical system 30 enters the display element 7 and is reflected as the display light to the roof reflection surface 18a of the pentamirror 18. The reproduction light L reflected by the roof reflection surface 18 a is reflected by the front reflection surface 18 b and travels toward the eyepiece lens 9.

  FIG. 6 is a diagram illustrating a modification of the present embodiment. In the above-described embodiment, the display is superimposed on the subject image by causing the reproduction light to enter the display plate 7 via the pentaprism 8, but in this modification, the superposition optical system 20 is used instead of the display plate 7. It was made to superimpose using. In the modification shown in FIG. 6, the superimposing optical system 20 is disposed behind the eyepiece lens 9, but may be disposed between the eyepiece lens 9 and the pentaprism 8.

  The superimposing optical system 20 is provided with an optical block 21 on which a polarization beam splitter 21a as a polarization separation mirror is formed, a quarter wavelength plate 22 fixed on the back of the optical block 21, and a hologram mirror 23. The hologram mirror 23 and the quarter wavelength plate 22 are made of a member that is substantially transparent to the subject light F.

  The reproduction light L emitted from the lens 100 enters the optical block 21, and the S-polarized component of the reproduction light L is reflected by the polarization beam splitter 21a. The reflected S-polarized light becomes circularly polarized light by the quarter-wave plate 22 and is reflected by the hologram mirror 23. The hologram mirror 23 corresponds to the lens 101 in FIG. 1 and functions as a concave mirror for incident reproduction light. The reflected light reflected by the hologram mirror 23 enters the quarter wavelength plate 22 as circularly polarized light in the reverse direction, and becomes P polarized light by the quarter wavelength plate 22. This P-polarized light is transmitted through the polarization beam splitter 21 a and is superimposed on the subject light from the eyepiece 9.

The embodiment described above has the following operational effects.
(1) A light source 11 that emits illumination light, a hologram (hologram element 12) that receives illumination light and emits a plurality of reproduction lights corresponding to a plurality of reproduction images, and an optical path of the plurality of reproduction lights L1 to L5 Provided with the light shielding element 13 that selectively transmits the reproduction lights L1 to L5, a plurality of reproduction lights can be generated from one illumination light, and the display device can be miniaturized. it can.
(2) Since the hologram is used, reproduction light corresponding to a plurality of types of reproduction images can be generated, and various forms of display can be performed with a pair of light sources and holograms. In particular, when a computer generated hologram is used, it is possible to easily form interference fringes for generating a plurality of types of reproduced images and to display an arbitrary shape.
(3) The light shielding element 13 may be a liquid crystal hologram element. In that case, a lens function or the like can be added to the light shielding element 13 itself, and the display device can be further miniaturized.

  In the above-described embodiment, the semiconductor laser is used as the light source 11, but the present invention is not limited thereto, and for example, an LED or the like may be used. However, in the case of a semiconductor laser, light with high luminance can be obtained, and therefore there is an advantage that bright display light can be obtained even when a plurality of reproduction lights are generated. In the above-described embodiment, the display in the viewfinder of the camera has been described as an example. However, the present invention is not limited to the camera and can be applied to display devices of various devices. In addition, the present invention is not limited to the above embodiment as long as the characteristics of the present invention are not impaired.

It is a figure explaining one Embodiment of the display apparatus by this invention, and applies a display apparatus to the display apparatus in a finder of a camera. It is a figure explaining the production | generation of the display light by the display apparatus in a finder. FIG. 6 is a cross-sectional view of the vicinity of the display unit 70 of the display board 7. It is a figure explaining the function of a light-shielding part. It is a figure which shows the structure at the time of using the hollow pentamirror 18. FIG. It is a figure which shows a modification.

Explanation of symbols

  6: focusing plate, 7: display plate, 8: pentaprism, 9: eyepiece lens, 10: projection optical system, 11: light source, 12: hologram element, 13: light shielding element, 70: display unit, 131-135: light shielding Part, 700: microprism, L1-L5: reproduction light

Claims (7)

A focusing screen on which a subject image is formed by a taking lens;
A display plate disposed close to the focusing screen in the optical path of the transmitted light transmitted through the photographing lens;
An observation optical system for observing the subject image formed on the focusing screen through the display plate;
A light source that emits illumination luminous flux;
A hologram that emits the incident illumination light beam through a single diffraction grating as a plurality of reproduction light beams in different directions;
A light shielding element that is disposed in an optical path of each of the plurality of reproduction light beams and individually transmits or blocks each of the plurality of reproduction light beams;
An optical system for allowing the reproduction light beam transmitted through the light-shielding element to enter the display plate,
The display plate has a reflection part that reflects the reproduction light beam incident by the optical system to the observation optical system,
The camera according to claim 1, wherein the observation optical system observes the subject image formed on the focusing screen and the reproduction light beam reflected by the reflection unit. The camera of claim 1,
The camera, wherein the hologram is a computer generated hologram. The camera according to claim 1 or 2,
The camera, wherein the light shielding element is a liquid crystal hologram. The camera according to any one of claims 1 to 3,
The reproduction beam generates a reproduction image representing photographing information on the display board. A light source that emits illumination luminous flux;
A hologram that emits the incident illumination light beam through a single diffraction grating as a plurality of reproduction light beams in different directions;
A light shielding element that is disposed in an optical path of each of the plurality of reproduction light beams and individually transmits or blocks each of the plurality of reproduction light beams,
A display device that displays a hologram reproduction image by a reproduction light beam transmitted through the light shielding element. The display device according to claim 5,
The display device, wherein the hologram is a computer generated hologram. The display device according to claim 5 or 6,
The display device, wherein the light shielding element is a liquid crystal hologram element.

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