JPWO2018164058A1 - Optical device - Google Patents

Abstract

The optical device displays a first optical element that reflects light having a first wavelength out of light incident through an optical system that forms a subject image with a higher reflectance than light having a second wavelength, and displays an image. The display unit, the light reflected by the first optical element and the light emitted from the display unit are incident, and the first wavelength of the light reflected by the first optical element is incident. Of the light having the first transmittance, the light having the second wavelength and the second transmittance higher than the first transmittance, and being emitted from the display unit and incident. A second optical element that reflects the light of the first wavelength with a first reflectance and reflects the light of the second wavelength with a second reflectance lower than the first reflectance; An observation unit capable of observing the subject image formed by the light reflected by the first optical element and the image displayed on the display unit in an overlapping manner.

Description

  The present invention relates to optical devices.

There is known an imaging device that superimposes and displays an optically input subject image and an image obtained by capturing the subject using a half mirror (Patent Document 1).
In the above image pickup device, the brightness of the observed image is dark.

Japanese Patent Laid-Open No. 2012-63721

According to the first aspect of the present invention, the optical device reflects the light of the first wavelength of the light incident through the optical system forming the subject image with a higher reflectance than the light of the second wavelength. The first optical element, the display section for displaying an image, the light reflected by the first optical element and the light emitted from the display section are incident and reflected by the first optical element. Of the incident light, the light of the first wavelength is transmitted with a first transmittance, the light of the second wavelength is transmitted with a second transmittance higher than the first transmittance, and the display The light of the first wavelength reflected with a first reflectance, and the light of the second wavelength with a second reflectance lower than the first reflectance, of the light emitted from the part and incident. A second optical element, and the object image by the light reflected by the first optical element and the image displayed on the display unit. Overlapping a comprises a observable observation unit.
According to the second aspect of the present invention, the optical device reflects the light of the first wavelength of the light incident through the optical system forming the subject image with a higher reflectance than the light of the second wavelength. The first optical element, the display section for displaying an image, the light reflected by the first optical element and the light emitted from the display section are incident and reflected by the first optical element. Of the incident light, the light of the first wavelength is reflected with a first reflectance, the light of the second wavelength is reflected with a second reflectance higher than the first reflectance, and the display is The light having the first wavelength transmitted through the light emitted from the section at the first transmittance, and the light having the second wavelength transmitted at the second transmittance lower than the first transmittance. A second optical element, and an image formed by the light transmitted by the first optical element, the subject image, and the image displayed on the display unit. Overlapping the image comprises a observable observation unit.
According to a third aspect of the present invention, an optical device displays a first optical element that transmits light having a first wavelength of incident light with a higher transmittance than light having a second wavelength, and an image. Of the light having passed through the first optical element and the light emitted from the display section are incident, and the light having the first wavelength out of the light that has passed through the first optical element and is incident. The light having the first transmittance is transmitted, the light having the second wavelength is transmitted at the second transmittance higher than the first transmittance, and the first light among the lights incident from the display unit is transmitted. A second optical element that reflects light of a wavelength with a first reflectance and reflects light of the second wavelength with a second reflectance that is lower than the first reflectance; An observation unit is provided which allows an image formed by the light transmitted by the optical element and the image displayed on the display unit to be observed in an overlapping manner.
According to the fourth aspect of the present invention, the optical device displays the first optical element that transmits the light of the first wavelength of the incident light with a higher transmittance than the light of the second wavelength, and displays an image. Of the light having passed through the first optical element and the light emitted from the display section are incident, and the light having the first wavelength out of the light that has passed through the first optical element and is incident. The light having the first reflectance is reflected, the light having the second wavelength is reflected at the second reflectance that is higher than the first reflectance, and the first light among the light incident from the display unit is reflected. A second optical element that transmits light of a wavelength at a first transmittance and transmits light of the second wavelength at a second transmittance lower than the first transmittance; An observation unit is provided that allows an image formed by the light reflected or transmitted by the optical element and the image displayed on the display unit to be observed in an overlapping manner.
According to a fifth aspect of the present invention, an optical device includes a light emitting unit that emits more light of a first wavelength than light of a second wavelength different from the first wavelength; A reflectance of light of a first wavelength is higher than a reflectance of light of the second wavelength, or a transmittance of light of the first wavelength is higher than a transmittance of light of the second wavelength; The optical element and the first optical element, the transmittance of the light of the second wavelength is higher than the transmittance of the light of the second wavelength with respect to the incident light, and the light emission is performed. A second optical element in which the reflectance of the light of the first wavelength is higher than the reflectance of the light of the second wavelength with respect to the light incident from the section.
According to a sixth aspect of the present invention, an optical device includes a light emitting unit that emits more light of a first wavelength than light of a second wavelength different from the first wavelength; A reflectance of light of a first wavelength is higher than a reflectance of light of the second wavelength, or a transmittance of light of the first wavelength is higher than a transmittance of light of the second wavelength; The optical element and the first optical element reflect the light or enter the light having a reflectance of the second wavelength is higher than the reflectance of the light of the first wavelength, and the light is emitted. A second optical element in which the transmittance of the light of the first wavelength is higher than the transmittance of the light of the second wavelength with respect to the light incident from the section.
According to the seventh aspect of the present invention, the optical device reflects the light of the first wavelength of the light incident through the optical system forming the subject image with a higher reflectance than the light of the second wavelength. The first optical element and the light reflected by the first optical element are incident, and the light of the first wavelength among the light reflected by the first optical element and incident is the first transmittance. Observing the subject image by the light that has been transmitted through the second wavelength and has the second transmittance that is higher than the first transmittance and that is reflected by the first optical element. And a section.

It is a figure which shows the structural example of the imaging device which applied the optical device which concerns on 1st Embodiment. It is a figure which shows an example of the light emission spectral characteristic of the image display part which concerns on 1st Embodiment. It is a figure which shows an example of the reflection spectral characteristic of the beam splitter which concerns on 1st Embodiment. It is a figure which shows an example of the spectral characteristic of the light of the image display part reflected by the beam splitter which concerns on 1st Embodiment. It is a figure which shows an example of the transmission spectral characteristic of the beam splitter which concerns on 1st Embodiment. It is a figure which shows an example of the reflection spectral characteristic of the main mirror which concerns on 1st Embodiment. It is a figure which shows an example of the spectral characteristic of the light observed by the eyepiece part 49 of the imaging device which concerns on 1st Embodiment. It is a figure which shows the structural example of the imaging device which applied the optical device which concerns on 2nd Embodiment. It is a figure which shows an example of the transmission spectral characteristic of the spectral filter which concerns on 2nd Embodiment. It is a figure which shows an example of the spectral characteristic of the light observed by the eyepiece part 49 of the imaging device which concerns on 2nd Embodiment.

(First embodiment)
FIG. 1 is a diagram illustrating a configuration example of an electronic camera 1 (hereinafter, referred to as a camera 1) that is an example of an imaging device to which the optical device according to the first embodiment is applied. The camera 1 includes a camera body 2 and a lens unit 3. The lens unit 3 is, for example, an interchangeable lens, and is detachably attached to the camera body 2 via a mount unit (not shown). The camera 1 may be a camera in which the camera body 2 and the lens unit 3 are integrally configured.

  The lens unit 3 includes a photographing optical system (imaging optical system) 31. Although the photographic optical system 31 is illustrated as a single lens for simplification of the drawing, the photographic optical system 31 includes a plurality of lenses including a focus adjustment lens (focus lens) and an aperture, and is included in the image pickup element of the camera body 2. A subject image is formed on the imaging surface. The focus adjustment lens of the photographing optical system 31 moves back and forth in the optical axis L1 direction based on a signal output from the control unit of the camera body 2. The aperture diameter of the diaphragm of the photographing optical system 31 is controlled based on a signal output from the control unit of the camera body 2.

  The camera body 2 includes a main mirror 21, a sub mirror 22, an observation optical system 40, an autofocus (AF) sensor 23, an image pickup device 24, a control unit 25, a memory 26, a display unit 27, and an operation unit. And part 28.

  The main mirror 21 is composed of a beam splitter having a spectral characteristic described later, is arranged between the photographing optical system 31 and the image pickup element 24, and subject light is incident through the photographing optical system 31. The beam splitter is, for example, a thin film mirror (pellicle mirror) having a dielectric multilayer film deposited thereon. The main mirror 21 may be flat glass on which this thin film is formed. The main mirror 21 can be moved between a position (mirror down position shown in FIG. 1) obliquely arranged with respect to the optical axis L1 in the optical path of light from a subject and a position (mirror up position) retracted from the optical path. Is. That is, the main mirror 21 has a function as a so-called quick return mirror.

  The sub-mirror 22 is arranged between the main mirror 21 and the image sensor 24, and reflects a part of the light transmitted through the main mirror 21 toward the AF sensor 23. When the main mirror 21 is moved to the mirror-up position, the sub mirror 22 is moved to a position retracted from the optical path of the light from the subject in cooperation with the main mirror 21.

  The AF sensor 23 is composed of, for example, a line sensor or the like, and photoelectrically converts light from the subject reflected by the sub mirror 22 to generate a pair of focus detection signals used for phase-difference type automatic focus adjustment (AF). The AF sensor 23 outputs the generated pair of focus detection signals, that is, the first focus detection signal and the second focus detection signal to the control unit 25. The first and second focus detection signals photoelectrically convert the first and second images by the first and second light fluxes that have respectively passed through the first and second regions of the exit pupil of the photographing optical system 31. Is a signal generated by

  The image sensor 24 is, for example, a CMOS image sensor or a CCD image sensor. The image pickup device 24 receives the light flux that has passed through the photographing optical system 31 and picks up a subject image. In the image sensor 24, a plurality of pixels each having a photoelectric conversion unit are arranged in the row direction and the column direction. The photoelectric conversion unit is composed of, for example, a photodiode (PD). The image sensor 24 photoelectrically converts the received light to generate a signal, and outputs the generated signal to the control unit 25.

  The memory 26 is a recording medium such as a memory card. Image data and the like are recorded in the memory 26. The writing of data to the memory 26 and the reading of data from the memory 26 are performed by the control unit 25. The display unit 27 displays an image based on the image data, information regarding shooting such as a shutter speed and an aperture value, and a menu screen. The operation unit 28 includes various setting switches such as a release button and a power switch, and outputs an operation signal corresponding to each operation to the control unit 25.

  The control unit 25 includes a CPU, a ROM, a RAM, and the like, and controls each unit of the camera 1 based on a control program. The control unit 25 performs various kinds of image processing on the signal output from the image sensor 24 to generate image data (still image data or moving image data). The image processing includes, for example, known image processing such as gradation conversion processing, color interpolation processing, and edge enhancement processing.

  The control unit 25 uses the pair of focus detection signals output from the AF sensor 23 to calculate the defocus amount by a known phase difference method. Specifically, the control unit 25 detects the image shift amount of the first and second images based on the pair of focus detection signals. The control unit 25 calculates the defocus amount based on the detected image shift amount. The focus adjustment is performed by driving the focus adjustment lens according to the defocus amount.

  When the above-mentioned main mirror 21 is arranged in the down position shown in FIG. 1, a part of the light flux passing through the photographing optical system 31 is reflected upward (upward in the drawing) by the main mirror 21, and the photographing optical system 31 The other part of the light flux that has passed through is transmitted. The light flux reflected by the main mirror 21 is guided to the observation optical system 40. The light flux transmitted through the main mirror 21 is reflected downward (downward in the plane of the drawing) by the submirror 22, and is guided to the AF sensor 23.

  That is, when the main mirror 21 is located at the down position, the subject light is guided to each of the observation optical system 40 and the AF sensor 23. As a result, the user can observe the subject image through the observation optical system 40, and the AF sensor 23 detects the focus.

  When the main mirror 21 is located at the up position, the light flux that has passed through the photographing optical system 31 is guided to the image sensor 24. The control unit 25 moves the main mirror 21 to the up position when the full-press operation of the release button is detected, for example, based on the operation signal output from the operation unit 28. Then, the control unit 25 causes the image sensor 24 to capture a subject image, and generates image data using the signal output from the image sensor 24. The control unit 25 records the generated image data in the memory 26.

  The observation optical system 40 includes a focusing screen 41, a pentaprism 42, a beam splitter 43, an image display unit 44, an EVF lens 45, an eyepiece lens 46, and an eyepiece unit 49. As described above, when the main mirror 21 is located at the down position, the light flux from the subject reflected by the main mirror 21 enters the observation optical system 40.

  The focusing screen 41 is arranged at a position optically equivalent to the image pickup element 24, and a subject image is formed by the light flux reflected by the main mirror 21. That is, a subject image formed by the light flux that has passed through the photographing optical system 31 is formed on the focusing screen 41 via the main mirror 21. The pentaprism 42 has a plurality of reflecting surfaces, reflects the subject image formed on the focusing screen 41, and inverts (converts) it into an erect image.

  The image display unit 44 is, for example, a liquid crystal display device having a liquid crystal panel and a light source. The liquid crystal panel is composed of a plurality of pixels (liquid crystal pixels) arranged in rows and columns. The liquid crystal panel is composed of, for example, three types of pixels having R (red), G (green), and B (blue) color filters. The light source of the liquid crystal display device includes a plurality of LEDs (Light Emitting Diodes) and the like, and functions as a backlight of the liquid crystal panel. The light from the light source of the image display unit 44 passes through the color filters of the RGB pixels and is guided to the eyepiece lens 46 via the EVF lens 45 and the beam splitter 43.

  The image display unit 44 displays a color image by controlling the transmission of light from the light source using pixels of each color of RGB. In the present embodiment, the image display unit 44 functions as an electronic view finder (EVF). The image display unit 44 displays an image based on image data generated based on a signal from the image pickup device 24, information regarding shooting such as a shutter speed and an aperture value, and the like. Further, the image display unit 44 functions as a light emitting unit that emits light of each wavelength (band) of RGB because the spectral characteristics of the light emitted by the RGB color filters are adjusted. The image display unit 44 may be a display device using an organic EL.

FIG. 2 is a diagram showing an example of emission spectral characteristics of the image display unit 44 according to the first embodiment. In FIG. 2, the vertical axis represents luminance (unit: cd / mm ² ) and the horizontal axis represents wavelength (unit: nm). Since the light from the light source of the image display unit 44 is emitted through the RGB color filters, the image display unit 44 emits more light of each wavelength of RGB than light of a wavelength different from the wavelength of RGB. .. As shown in FIG. 2, the emission brightness of the light emitted by the image display unit 44 has three peaks at a B wavelength near 450 nm, a G wavelength near 530 nm, and an R wavelength near 630 nm. There is. The emission brightness of these three peaks of RGB is, for example, 1000 cd / mm ² .

  In FIG. 1, the beam splitter 43 has, for example, a surface on which a dielectric multilayer film is deposited, and has a spectral characteristic described later. The beam splitter 43 is arranged on the optical path of light from the subject passing through the pentaprism 42. The light flux that has passed through the pentaprism 42 enters the beam splitter 43. A part of the light flux that has passed through the penta prism 42 passes through the beam splitter 43 and is guided to the eyepiece lens 46. Further, the light beam emitted from the image display unit 44 enters the beam splitter 43. A part of the light flux emitted from the image display unit 44 is reflected by the beam splitter 43 and guided to the eyepiece lens 46. The beam splitter 43 may be a thin film mirror having a dielectric multilayer film deposited thereon.

  The light from the subject that passes through the beam splitter 43 and the light that is emitted from the image display unit 44 and reflected by the beam splitter 43 are superposed (combined) and guided to the eyepiece lens 46. Accordingly, the user can observe the image displayed by the image display unit 44 and the subject image via the eyepiece unit 49 and the eyepiece lens 46.

  In the present embodiment, as will be described later in detail, the beam splitter 43 has a reflectance of light of each wavelength of RGB with respect to light incident from the image display unit 44, of light having a wavelength different from the wavelength of RGB. It has a reflection spectral characteristic higher than the reflectance. In the present embodiment, the reflection spectral characteristic of the beam splitter 43 is a characteristic that mainly reflects the light of the wavelengths of RGB from the image display unit 44, so that the beam splitter with respect to the subject light guided from the main mirror 21. The transmittance of 43 is secured.

  Further, the beam splitter 43 has a transmittance of light having a wavelength different from the wavelengths of R, G, and B with respect to the light reflected by the main mirror 21 and incident on the beam splitter 43 more than that of light of each of the R, G, and B wavelengths. It has high transmission spectral characteristics. Since the beam splitter 43 does not have a constant (substantially flat) transmittance in a specific wavelength range (for example, a visible light wavelength range from about 350 nm to about 680 nm), the main mirror 21 is temporarily fixed in the specific wavelength range. In the case of having a (substantially flat) reflectance of, the tint of the subject image observed through the beam splitter 43 changes. That is, the subject image observed through the observation optical system 40 has a color different from the actual color of the subject.

  Therefore, in the main mirror 21 according to the present embodiment, the reflectance of light of each wavelength of RGB is higher than the reflectance of light of a wavelength different from the wavelength of RGB with respect to the light passing through the photographing optical system 31. It has reflection spectral characteristics. Accordingly, it is possible to suppress a change in the tint of the subject image observed through the observation optical system 40, and the user can observe the subject image in a natural tint. The details will be described below.

  FIG. 3 is a diagram showing an example of reflection spectral characteristics of the beam splitter 43 according to the first embodiment. In FIG. 3, the vertical axis represents reflectance (unit is%), and the horizontal axis represents wavelength (unit is nm). As shown in FIG. 3, the reflectance of the beam splitter 43 has three peaks at a B wavelength near 450 nm, a G wavelength near 530 nm, and an R wavelength near 630 nm. The reflectance of the three peaks in each wavelength region of these RGB is, for example, about 30%. Further, the beam splitter 43 has a substantially constant reflectance (for example, about 0%) at a wavelength different from the wavelengths of RGB.

  As described above, the beam splitter 43 has a reflectance spectral characteristic in which the reflectance of the light of each wavelength of RGB is higher than the reflectance of the light of the wavelength different from the wavelength of RGB with respect to the light incident from the image display unit 44. Have. As a result, the beam splitter 43 reflects the light of each wavelength of RGB that is incident from the image display unit 44 more than the light of a wavelength different from the wavelength of RGB.

  As shown in FIG. 2, the emission luminance of the light that enters the beam splitter 43 from the image display unit 44 is 1000 cd / mm 2 at each wavelength of RGB near 450 nm, near 530 nm, and near 630 nm. Further, the beam splitter 43 has a reflectance of about 30% with respect to the light of each wavelength of RGB that is incident from the image display unit 44, as described above with reference to FIG. In this case, the spectral characteristic of the light of the image display section 44 reflected by the beam splitter 43 is as shown in FIG.

FIG. 4 is a diagram showing an example of spectral characteristics of light of the image display unit 44 reflected by the beam splitter 43 according to the first embodiment. In FIG. 4, the vertical axis represents luminance (unit: cd / mm ² ) and the horizontal axis represents wavelength (unit: nm). As shown in FIG. 4, the brightness of the light of the image display section 44 reflected by the beam splitter 43 becomes 300 cd / mm ² in the vicinity of 450 nm, in the vicinity of 530 nm, and in the vicinity of 630 nm, respectively. This means that light having sufficient brightness for the user to observe is guided to the eyepiece lens 46.

  In this way, the beam splitter 43 reflects the light of the RGB wavelengths from the image display unit 44 toward the eyepiece lens 46 more than the light of the wavelengths different from the RGB wavelengths. That is, the beam splitter 43 functions as a filter that mainly reflects the light of the RGB wavelengths with respect to the light incident from the image display unit 44. Therefore, the visibility of the image of the image display unit 44 observed through the observation optical system 40 can be secured. The reflectance of the beam splitter 43 is determined by the material of the film forming the beam splitter 43, the number of stacked films, the film thickness, and the like. Therefore, for example, the reflectance of the beam splitter 43 can be increased and the emission brightness of the light source of the image display unit 44 can be reduced, and the power consumption of the light source can be reduced.

  FIG. 5 is a diagram showing an example of transmission spectral characteristics of the beam splitter 43 according to the first embodiment. In FIG. 5, the vertical axis represents the transmittance (unit is%), and the horizontal axis represents the wavelength (unit is nm). The transmittance of the beam splitter 43 is, for example, about 100% at a wavelength different from the RGB wavelengths. Further, the transmittance of the beam splitter 43 decreases at a B wavelength near 450 nm, a G wavelength near 530 nm, and an R wavelength near 630 nm, and becomes about 70%, for example.

  As described above, the beam splitter 43 has a transmittance of light having a wavelength different from the wavelengths of RGB with respect to the light reflected by the main mirror 21 and incident on the beam splitter 43. It has a higher transmission spectral characteristic than that. Therefore, the beam splitter 43 transmits a large amount of light having a wavelength different from the wavelengths of RGB among the light reflected by the main mirror 21 and incident on the beam splitter 43.

  FIG. 6 is a diagram showing an example of reflection spectral characteristics of the main mirror 21 according to the first embodiment. In FIG. 6, the vertical axis represents reflectance (unit is%), and the horizontal axis represents wavelength (unit is nm). As shown in FIG. 6, the reflectance of the main mirror 21 has three peaks at a B wavelength near 450 nm, a G wavelength near 530 nm, and an R wavelength near 630 nm. The reflectance of these three peaks of RGB is, for example, about 100%. Further, the main mirror 21 has a substantially constant reflectance (for example, about 70%) at a wavelength different from the wavelength of RGB in a specific wavelength region (for example, visible light region). It is preferable to adjust the reflection spectral characteristic of the main mirror 21 so that the amount of light necessary for focus detection by the AF sensor 23 and the control unit 25 is guided to the AF sensor 23. For example, when the AF sensor 23 and the control unit 25 perform focus detection based on light of each wavelength of RGB, the reflectance at the three peaks of RGB described above may be set to a value smaller than 100%.

  As described above, the main mirror 21 has a reflection spectral characteristic in which the reflectance of the light of each wavelength of RGB is higher than the reflectance of the light of the wavelength different from the wavelength of RGB with respect to the light passing through the photographing optical system 31. Have. As a result, the main mirror 21 reflects more of the light of each wavelength of RGB among the light passing through the photographing optical system 31 than the light of the wavelength different from the wavelength of RGB.

  The reflectance of the main mirror 21 is determined by the material of the film forming the main mirror 21, the number of laminated films, the film thickness, and the like. In the present embodiment, the difference between the reflectance of light of each wavelength of RGB of the beam splitter 43 and the reflectance of light of wavelength different from the wavelength of RGB, and the reflectance of light of each wavelength of RGB of the main mirror 21. The reflectance of each of the beam splitter 43 and the main mirror 21 is adjusted so that the difference between the reflectance of light having a wavelength different from that of RGB and the reflectance of light having a wavelength different from that of RGB are substantially equal.

  In the example shown in FIG. 3, the difference between the reflectance of the beam splitter 43 for the light of each wavelength of RGB and the reflectance of the beam splitter 43 for the light of a wavelength different from the wavelength of RGB is about 30%. Further, in the example shown in FIG. 6, the difference between the reflectance of the main mirror 21 for the light of each wavelength of RGB and the reflectance of the main mirror 21 for the light of a wavelength different from the wavelength of RGB is about 30%. .. Therefore, the difference between the reflectance of the light of each wavelength of RGB of the beam splitter 43 and the reflectance of the light of a wavelength different from the wavelength of RGB, the reflectance of the light of each wavelength of RGB of the main mirror 21, and the reflectance of RGB The difference between the reflectance of light having a different wavelength and the reflectance of light is substantially equal.

  FIG. 7 is a diagram showing an example of spectral characteristics of a light beam observed at the eyepiece section 49 of the image pickup apparatus according to the first embodiment. In FIG. 7, the vertical axis represents the transmittance (unit is%), and the horizontal axis represents the wavelength (unit is nm). The spectral characteristics shown in FIG. 7 are determined based on the reflection spectral characteristics of the main mirror 21 and the transmission spectral characteristics of the beam splitter 43, and the amount of light that the subject light passing through the photographing optical system 31 has passed through the main mirror 21 and the beam splitter 43. Represents the ratio of. That is, the spectral characteristic shown in FIG. 7 indicates the spectral characteristic of the subject light finally guided to the eyepiece lens 46. As shown in FIG. 7, the spectral characteristic of the subject light has a transmittance of about 70% in a specific wavelength range (for example, a visible light range), and the spectral characteristic is almost flat (the main mirror 21 and the beam splitter 43 have The same as the spectral characteristics of the subject light flux when there is no intervening).

  As described above, the spectral characteristic after the subject light is transmitted is a spectral characteristic in which the transmittance is substantially constant in the specific wavelength range. Accordingly, it is possible to suppress the change in the tint of the subject image observed through the observation optical system 40. The spectral characteristic for the subject light is not limited to the flat spectral characteristic shown in FIG. The reflection spectral characteristic of the main mirror 21 and the transmission spectral characteristic of the beam splitter 43 may be adjusted to set the spectral characteristic for the subject light so that the tint of the subject image does not make the user feel uncomfortable.

  Generally, when the beam splitter 43 is arranged in order to superimpose the image of the image display unit 44 on the subject image, the subject light is reduced by the beam splitter 43. When the main mirror 21 has a constant (substantially flat) reflectance and the beam splitter 43 has a constant (substantially flat) transmittance, the reflectance of the main mirror 21 is set to about 70% and the beam splitter 43 If the transmittance of is about 70%, the spectral characteristic for the subject light is about 49%.

  In the present embodiment, as shown in FIG. 3, the reflection spectral characteristic of the beam splitter 43 is set to a characteristic that mainly reflects light of RGB wavelengths, so that as shown in FIG. Secures the transmittance for light of different wavelengths. In the example shown in FIG. 5, the transmittance of the beam splitter 43 is about 70% at the wavelength of RGB and about 100% at the wavelength different from the wavelength of RGB. Further, as shown in FIG. 6, the main mirror 21 secures the reflectance for the light of the RGB wavelengths of the subject light. In the example shown in FIG. 6, the reflectance of the main mirror 21 is about 100% at the wavelength of RGB and about 70% at the wavelength different from the wavelength of RGB. With the above-described configuration, in the present embodiment, the spectral characteristic of the eyepiece 49 with respect to the subject light has a transmittance of about 70% in a specific wavelength range such as the wavelength range of visible light. That is, it is possible to obtain the same spectral characteristics as when the beam splitter 43 is not arranged. For this reason, it is possible to improve the visibility of the subject image by the photographing optical system 31 observed through the observation optical system 40.

According to the above-described embodiment, the following operational effects can be obtained.
(1) The optical device reflects the light of the first wavelength of the light incident through the optical system (imaging optical system 31) that forms the subject image with a higher reflectance than the light of the second wavelength. The first optical element (main mirror 21), the display section (image display section 44) for displaying an image, the light reflected by the first optical element and the light emitted from the display section are incident, Of the light reflected and incident on the optical element of the first wavelength, the light of the first wavelength is transmitted at the first transmittance, and the light of the second wavelength is transmitted at the second transmittance higher than the first transmittance. Then, of the light emitted from the display unit and incident, the light of the first wavelength is reflected at the first reflectance, and the light of the second wavelength is reflected at the second reflectance lower than the first reflectance. It has a second optical element (beam splitter 43) that is used for displaying the subject image by the light reflected by the first optical element and the display section. Overlapping the image comprises observable observation portion (the observation optical system 40), the. Since it did in this way, the change of the tint of the to-be-photographed image observed via the beam splitter 43 can be suppressed. Further, it is possible to obtain the same spectral characteristics as when the beam splitter 43 is not arranged.
(2) The optical device includes a light emitting unit (image display unit 44) that emits more light of the first wavelength than light of the second wavelength different from the first wavelength, and the reflectance of the light of the first wavelength. Alternatively, the first optical member (main mirror 21) whose transmittance is higher than the reflectance or transmittance of the light of the second wavelength and the second optical member for the light reflected or transmitted through the first optical member Is higher than the transmittance of the light of the first wavelength, and the reflectance of the light of the first wavelength is higher than the reflectance of the light of the second wavelength with respect to the light incident from the light emitting portion. And a second optical member (beam splitter 43) which is also higher. Since it did in this way, the change of the tint of the to-be-photographed image observed via the beam splitter 43 can be suppressed. Further, it is possible to obtain the same spectral characteristics as when the beam splitter 43 is not arranged.

(Second embodiment)
An optical device according to the second embodiment will be described with reference to the drawings. FIG. 8 is a diagram showing a configuration example of a camera 1 which is an example of an imaging device to which the optical device according to the second embodiment is applied. In the first embodiment, the light from the subject reflected by the main mirror 21 and the light from the image display unit 44 reflected by the beam splitter 43 are superposed and guided to the eyepiece lens 46. On the other hand, in the second embodiment, the light from the subject that passes through the spectral filter 47 and the light from the image display unit 44 that is reflected by the beam splitter 43 are superposed and guided to the eyepiece lens 46. .. In the drawings, the same or corresponding parts as those of the first embodiment are designated by the same reference numerals, and the differences will be mainly described.

  The observation optical system 40 according to the second embodiment includes a spectral filter 47 and an objective lens 48. The spectral filter 47 is, for example, a thin film mirror (pellicle mirror) having a dielectric multilayer film deposited thereon. The spectral filter 47 is arranged in the optical path (optical axis L2) of the light from the subject. A light flux from the subject is incident on the spectral filter 47, and the spectral filter 47 transmits a part of the light flux from the subject. The light flux that has passed through the spectral filter 47 is guided to the beam splitter 43 via the objective lens 48. Although the spectral filter 47 and the objective lens 48 are arranged as shown in FIG. 8, the position of the spectral filter 47 and the position of the objective lens 48 (arrangement order) may be exchanged. That is, the light from the subject may pass through the objective lens 48 and enter the spectral filter 47.

  The light beam that has passed through the spectral filter 47 and the objective lens 48 enters the beam splitter 43. A part of the light flux that has passed through the spectral filter 47 and the objective lens 48 passes through the beam splitter 43 and is guided to the eyepiece lens 46. A part of the light beam emitted from the image display unit 44 is reflected by the beam splitter 43 and guided to the eyepiece lens 46. The light from the subject that passes through the spectral filter 47 and the light emitted by the image display unit 44 are superposed and guided to the eyepiece lens 46. Thus, the user can observe the optical subject image and the image displayed by the image display unit 44 via the eyepiece unit 49 and the eyepiece lens 46.

  FIG. 9 is a diagram showing an example of transmission spectral characteristics of the spectral filter 47 according to the second embodiment. In FIG. 9, the vertical axis represents the transmittance (unit is%), and the horizontal axis represents the wavelength (unit is nm). As shown in FIG. 9, the transmittance of the spectral filter 47 has three peaks at a B wavelength near 450 nm, a G wavelength near 530 nm, and an R wavelength near 630 nm. The transmittance of these three RGB peaks is, for example, about 100%. Further, the spectral filter 47 has a substantially constant transmittance (for example, about 85%) at a wavelength different from the wavelength of RGB in the specific wavelength band (for example, visible light region). As described above, the spectral filter 47 has a transmission spectral characteristic that the transmittance of light of each wavelength of RGB is higher than the transmittance of light of wavelength different from the wavelength of RGB with respect to the subject light.

  Further, in the present embodiment, the difference between the transmittance of the light of each wavelength of RGB of the spectral filter 47 and the transmittance of the light of a wavelength different from the wavelength of RGB is the difference of the light of each wavelength of RGB of the beam splitter 43. The respective transmittances of the spectral filter 47 and the beam splitter 43 are adjusted so as to be smaller than the difference between the transmittance and the transmittance of light having a wavelength different from that of RGB.

  In the example shown in FIG. 5, the difference between the transmittance of the beam splitter 43 for the light of each wavelength of RGB and the transmittance of the beam splitter 43 for the light of a wavelength different from the wavelength of RGB is about 30%. Further, in the example shown in FIG. 9, the difference between the transmittance of the spectral filter 47 for light of each wavelength of RGB and the transmittance of the spectral filter 47 for light of a wavelength different from the wavelength of RGB is about 15%. Become. This makes it possible to secure the transmitted light amount of the subject light while suppressing the change in the tint of the subject image. Below, it demonstrates using FIG.

  FIG. 10 is a diagram showing an example of spectral characteristics of a light beam observed at the eyepiece section 49 of the image pickup apparatus according to the second embodiment. In FIG. 10, the vertical axis represents the transmittance (unit is%), and the horizontal axis represents the wavelength (unit is nm). The spectral characteristic shown in FIG. 10 is obtained based on the transmission spectral characteristic of the spectral filter 47 of FIG. 9 and the transmission spectral characteristic of the beam splitter 43 of FIG. 5, and the ratio of subject light passing through the spectral filter 47 and the beam splitter 43. Represents. As shown in FIG. 10, the spectral characteristics with respect to the subject light have a transmittance of about 70% with respect to the light of each wavelength of RGB, and have a wavelength of RGB within a specific wavelength range (for example, visible light range). Has a transmittance of about 85% for light of different wavelengths. That is, the spectral characteristic with respect to the subject light has a high transmittance of 70% or more in a specific wavelength range. Therefore, the visibility of the subject image observed through the observation optical system 40 can be improved.

  Further, in the example shown in FIG. 10, the difference between the transmittance for light of each wavelength of RGB and the transmittance for light of a wavelength different from the wavelength of RGB is about 15% or less, which is observed through the observation optical system 40. The change in the tint of the subject image is suppressed. Therefore, in the second embodiment, it is possible to suppress a change in the tint of the subject image and to secure the amount of transmitted light of the subject light to improve the visibility of the subject image.

In the above embodiment, both the light flux reflected by the main mirror 21 and the light flux transmitted by the spectral filter 47 are transmitted by the beam splitter 43, and the light flux emitted from the image display unit 44 is transmitted by the beam splitter 43. Although the light is reflected, the light reflected by the main mirror 21 or the light transmitted through the spectral filter 47 is reflected by the beam splitter 43, and the light emitted from the image display unit 44 is transmitted through the beam splitter 43. It may be configured.
In this case, the spectral characteristics of the beam splitter 43 are different from the relationships shown in FIGS. 3 and 5, for example, the reflectance for light of each wavelength of RGB is lower than the reflectance of light of a wavelength different from the wavelength of RGB, The transmittance of light of each wavelength of RGB is higher than the transmittance of light of a wavelength different from the wavelength of RGB. That is, the spectral characteristics are shown in which the vertical axis in FIG. 3 indicates the transmittance and the vertical axis in FIG. 5 indicates the reflectance.

  The following modifications are also within the scope of the present invention, and it is possible to combine one or more modifications with the above-described embodiment.

(Modification 1)
In the above-described embodiment, an example in which the beam splitter 43 has a reflection spectral characteristic in which the reflectance of light of each wavelength of RGB is higher than the reflectance of light of wavelength different from the wavelength of RGB has been described. The reflection spectral characteristic of 43 is not limited to this. The reflection spectral characteristic of the beam splitter 43 may be adjusted according to the light emission spectral characteristic of the image display unit 44 and the like. For example, the beam splitter 43 has a reflectance spectrum in which the reflectance of light in one wavelength range (for example, R wavelength range) is higher than the reflectance of light in a wavelength range different from the one wavelength range in the specific wavelength range. You may make it have a characteristic. For example, when the image display unit 44 mainly emits light in the R wavelength region, the beam splitter 43 causes the light reflectance in the R wavelength region to reflect light in a wavelength region different from the R wavelength region. It has a higher reflectance spectral characteristic than that.

  Further, the beam splitter 43 may have a reflection spectral characteristic in which the reflectance of light in two wavelength bands is higher than the reflectance of light in a wavelength band different from those two wavelength bands in the specific wavelength band. Good. Furthermore, the beam splitter 43 may have reflection spectral characteristics in which the reflectance of light in four or more wavelength bands is higher than the reflectance of light in wavelength bands different from those wavelength bands in the specific wavelength band. Good.

  Further, in the above-described embodiment, an example in which the main mirror 21 has a reflection spectral characteristic in which the reflectance of light of each wavelength of RGB is higher than the reflectance of light of wavelength different from the wavelength of RGB has been described. The reflection spectral characteristic of the main mirror 21 is not limited to this. The reflection spectral characteristic of the main mirror 21 may be adjusted according to the transmission spectral characteristic (or the reflection spectral characteristic) of the beam splitter 43. For example, the main mirror 21 may have a reflectance spectral characteristic in which the reflectance of light in one or two wavelength bands is higher than the reflectance of light in a wavelength band different from those wavelength bands. Further, the main mirror 21 may have reflection spectral characteristics in which the reflectance of light in four or more wavelength bands is higher than the reflectance of light in wavelength bands different from those wavelength bands.

  Furthermore, in the above-described second embodiment, an example in which the spectral filter 47 has a transmission spectral characteristic in which the transmittance of light of each wavelength of RGB is higher than the transmittance of light of wavelength different from the wavelength of RGB is described. However, the transmission spectral characteristic of the spectral filter 47 is not limited to this. The transmission spectral characteristic of the spectral filter 47 may be adjusted according to the transmission spectral characteristic of the beam splitter 43 or the like. For example, the spectral filter 47 has a transmission spectral characteristic in which the transmittance of light in one or two wavelength bands is higher than the transmittance of light in a wavelength band different from those wavelength bands of the specific wavelength band. May be. Further, the spectral filter 47 may have a transmission spectral characteristic in which the transmittance of light in four or more wavelength bands is higher than the transmittance of light in wavelength bands different from those wavelength bands.

(Modification 2)
In the above-described embodiment, the reflectance of the main mirror 21 is about 100% at the wavelength of RGB and about 70% at the wavelength different from the wavelength of RGB, but the reflectance of the wavelength different from the wavelength of RGB is more excellent. It may be high (for example, 80%). In this case, the reflectance of RGB at the beam splitter 43 may be lowered (for example, 20%), and the emission brightness of the light source of the image display unit 44 may be increased. This makes it possible to observe a brighter optical image.
On the other hand, when the EVF is used, the higher the reflectance of the beam splitter 43 is, the lower the light emission brightness of the light source of the image display unit 44 can be. Therefore, the power consumption of the light source can be reduced. In this case, since the light flux from the main mirror 21 is not necessary for observation, it is better to use a beam splitter having high RGB reflectance irrespective of the reflection spectral characteristics of the main mirror. Therefore, a plurality of types of beam splitters having different reflection spectral characteristics may be exchangeably provided. Alternatively, an optical element whose reflection spectral characteristic is variable (for example, a thin film is provided on the surface of a dimming mirror device that controls the amount of transmitted light or the amount of reflected light by switching between a mirror state and a transparent state by applying a voltage. An optical element) may be used.

(Modification 3)
The optical device described in the above embodiments may be applied to a range finder, a telescope, and binoculars.

Although various embodiments and modifications have been described above, the present invention is not limited to these contents. Other modes considered within the scope of the technical idea of the present invention are also included in the scope of the present invention.
For example, in the above-mentioned embodiment, even if the term "wavelength" is simply used, it is not limited to the one having the luminance at a single wavelength, but the one having the luminance at a constant width (band). It goes without saying that it is also good. When they have a certain width, for example, the wavelengths of R and G, B and G, and B and R may not be completely separated but may partially overlap. Further, the spectral characteristics of the image display unit, the main mirror, the spectral filter, and the beam splitter may be such that the wavelengths do not completely match, that is, the central wavelengths of the respective wavelength bands do not exactly match.

The disclosure content of the following priority basic application is incorporated herein by reference.
Japanese patent application 2017 No. 45291 (filed on March 9, 2017)

1 image pickup device, 21 main mirror, 23 AF sensor, 43 beam splitter, 44 image display unit, 46 eyepiece lens, 47 spectral filter

Claims (14)

A first optical element that reflects, with a higher reflectance than the light of the second wavelength, the light of the first wavelength of the light that has entered through the optical system that forms the subject image;
A display unit that displays images,
The light reflected by the first optical element and the light emitted from the display unit are incident, and the light of the first wavelength among the light reflected and incident by the first optical element is first Of the light having the second wavelength, the light having the second wavelength, the light having the second wavelength that is higher than the first transmittance, and the light having the second wavelength that is emitted from the display unit. Light having a first reflectance and light having a second wavelength at a second reflectance lower than the first reflectance, and the first optical element. An observation unit capable of superimposing and observing the subject image and the image displayed on the display unit by the light reflected by the element,
An optical device comprising. The optical device according to claim 1,
The difference between the reflectance of the light of the first wavelength and the reflectance of the light of the second wavelength in the first optical element, and the transmittance of the light of the first wavelength in the second optical element. And a difference between the transmittance of the light of the second wavelength and the transmittance of the second wavelength are substantially equal to each other. The optical device according to claim 1 or 2, wherein
The display unit emits light of a third wavelength different from the first wavelength and the second wavelength and light of the first wavelength more than light of the second wavelength,
The first optical element has a reflectance of light of the first and third wavelengths higher than a reflectance of light of the second wavelength,
The second optical element has a transmittance of light of the second wavelength that is higher than that of light of the first and third wavelengths with respect to light that is reflected and incident on the first optical element. An optical device having a high reflectance of light of the first and third wavelengths with respect to light incident from the display unit, and higher than the reflectance of light of the second wavelength. A first optical element that reflects, with a higher reflectance than the light of the second wavelength, the light of the first wavelength of the light that has entered through the optical system that forms the subject image;
A display unit that displays images,
The light reflected by the first optical element and the light emitted from the display unit are incident, and the light of the first wavelength among the light reflected and incident by the first optical element is first Of the light having the second wavelength, the light having the second wavelength, the light having the second wavelength, and the second wavelength having a second reflectance higher than the first reflectance. Light having a first transmittance and light having a second wavelength that has a second transmittance lower than the first transmittance. An observation unit capable of observing the image by the light transmitted through the element, the subject image, and the image displayed on the display unit in an overlapping manner,
An optical device comprising. The optical device according to claim 4,
The difference between the reflectance of the light of the first wavelength and the reflectance of the light of the second wavelength in the first optical element, and the reflectance of the light of the first wavelength in the second optical element. And the difference between the reflectance of the light of the second wavelength and the reflectance of the second wavelength are substantially equal. The optical device according to claim 4 or 5,
The display unit emits light of a third wavelength different from the first wavelength and the second wavelength and light of the first wavelength more than light of the second wavelength,
The first optical element has a reflectance of light of the first and third wavelengths higher than a reflectance of light of the second wavelength,
The second optical element has a reflectance of light of the second wavelength with respect to light incident on the first optical element that is higher than reflectance of light of the first and third wavelengths. An optical device having a high transmittance of light having the first and third wavelengths with respect to light incident from the display unit, and higher than a transmittance of light having the second wavelength. The optical device according to any one of claims 1 to 6,
An image pickup unit for picking up an image by the optical system,
The display unit is an optical device that displays an image based on the image data output from the imaging unit. A first optical element that transmits the light of the first wavelength of the incident light with a higher transmittance than the light of the second wavelength;
A display unit that displays images,
The light transmitted through the first optical element and the light emitted from the display unit are incident, and the light of the first wavelength among the light transmitted through the first optical element and incident is the first light. The light having the second wavelength is transmitted at a transmittance, the light having the second wavelength is transmitted at a second transmittance higher than the first transmittance, and the light having the first wavelength out of the light incident from the display unit is A second optical element which reflects at a reflectance of 1 and reflects a light of the second wavelength at a second reflectance lower than the first reflectance, and is transmitted by the first optical element. An observation unit capable of observing the image displayed by the light and the image displayed on the display unit in an overlapping manner,
An optical device comprising. The optical device according to claim 8,
The difference between the transmittance of the light of the first wavelength and the transmittance of the light of the second wavelength in the first optical element, and the reflectance of the light of the first wavelength in the second optical element. And the difference between the reflectance of the light of the second wavelength and the reflectance of the second wavelength are substantially equal. A first optical element that transmits the light of the first wavelength of the incident light with a higher transmittance than the light of the second wavelength;
A display unit that displays images,
The light transmitted through the first optical element and the light emitted from the display unit are incident, and the light of the first wavelength among the light transmitted through the first optical element and incident is the first light. The light having the second wavelength, the light having the second wavelength, the light having the second wavelength, and the light having the second wavelength that is higher than the first reflectance. A second optical element which transmits at a transmittance of 1 and transmits a light of the second wavelength at a second transmittance lower than the first transmittance, and is reflected by the first optical element or An observation unit capable of observing an image formed by the transmitted light and the image displayed on the display unit in an overlapping manner,
An optical device comprising. The optical device according to claim 10,
The difference between the transmittance of the light of the first wavelength and the transmittance of the light of the second wavelength in the first optical element, and the transmittance of the light of the first wavelength in the second optical element. And a difference between the transmittance of the light of the second wavelength and the transmittance of the second wavelength are substantially equal to each other. A light emitting unit that emits more light of a first wavelength than light of a second wavelength different from the first wavelength;
Of the incident light, the reflectance of the light of the first wavelength is higher than the reflectance of the light of the second wavelength, or the transmittance of the light of the first wavelength is of the light of the second wavelength. A first optical element having a transmittance higher than that;
Light incident on the first optical element after being reflected or transmitted through the light emitting section has a transmittance of light of the second wavelength higher than that of light of the first wavelength. A second optical element having a reflectance of light of the first wavelength higher than that of light of the second wavelength.
An optical device comprising. A light emitting unit that emits more light of a first wavelength than light of a second wavelength different from the first wavelength;
Of the incident light, the reflectance of the light of the first wavelength is higher than the reflectance of the light of the second wavelength, or the transmittance of the light of the first wavelength is of the light of the second wavelength. A first optical element having a transmittance higher than that;
Light incident from the light emitting unit has a reflectance of the light of the second wavelength higher than that of the light of the first wavelength with respect to the light reflected or transmitted through the first optical element. A second optical element having a transmittance of light of the first wavelength higher than that of light of the second wavelength.
An optical device comprising. A first optical element that reflects, with a higher reflectance than the light of the second wavelength, the light of the first wavelength of the light that has entered through the optical system that forms the subject image;
The light reflected by the first optical element is incident, the light of the first wavelength of the light reflected and incident by the first optical element is transmitted at a first transmittance, and the second light is transmitted. An observation unit capable of observing the subject image by the light reflected by the first optical element, the observation unit transmitting light of a wavelength of 2 with a second transmittance higher than the first transmittance,
An optical device comprising.

Images