Finder and imaging device

Abstract

To provide a viewfinder and imaging device with good visibility. [Solution] The finder comprises a first optical system, a second optical system, and a polarizing element. The second optical system includes a first polarizer that transmits light in a first polarization direction, and an optical element that controls the polarization direction of the light transmitted through the first polarizer. The polarizing element reflects at least a portion of the light that has passed through the first optical system and transmits light in a second polarization direction from the light that has passed through the second optical system.

Description

Technical Field

[0007]

[0001] The present invention relates to a finder and an imaging device equipped with the finder.

Background Art

[0002] As a hybrid view finder (HVF), a finder having both functions of an optical view finder (OVF) and an electronic view finder (EVF) is known (for example, Patent Documents 1-3, etc.).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

[0004] One embodiment according to the technology of the present disclosure provides a finder and an imaging device with good visibility.

Means for Solving the Problems

[0005] [(1)] A finder including a first optical system, a first polarizer that transmits light with a first polarization direction, and a second optical system including an optical member that controls the polarization direction of the light transmitted through the first polarizer, and a polarization element that reflects at least a part of the light that has passed through the first optical system and transmits the light with a second polarization direction among the light that has passed through the second optical system.

[0006] [(2)] The finder according to [(1)], wherein the optical member is a liquid crystal member.

[0007] [3] The finder according to [1] or [2], wherein the first polarizer and the polarizing element are related such that the transmittance of light in the second polarization direction is below a threshold.

[0008] [4] A finder according to any one of [1] to [3], wherein the first polarizer and polarizing element are in a relationship in which the first polarization direction and the second polarization direction intersect.

[0009] [5] A finder according to any one of [1] to [4], wherein the polarizing element is able to be adjusted relative to the direction of the transmission axis of the polarizing element with respect to the transmission axis of the first polarizer.

[0010] [6] The polarizing element is rotated around the optical axis of the second optical system to adjust the direction of the transmission axis of the polarizing element relative to the transmission axis of the first polarizer, as in the finder described in [5].

[0011] [7] The finder according to any one of [1] to [6], wherein the second optical system includes a negative power optical system, and the first polarizer and optical elements are positioned closer to the eyepiece than the negative power optical system.

[0012] [8] The finder as described in any one of [1] to [7], wherein the second optical system includes a positive power optical system, and the first polarizer and optical elements are positioned on the objective side of the positive power optical system.

[0013] [9] The finder according to any one of [1] to [8], further comprising a first quarter-wave plate and a second quarter-wave plate, wherein at least one optical element is disposed between the first quarter-wave plate and the second quarter-wave plate.

[0014]

[10] The finder according to [9], wherein the optical element positioned between the first quarter-wave plate and the second quarter-wave plate is a resin optical element.

[0015]

[11] The second optical system further includes a second polarizer that transmits light in the second polarization direction, and an optical member is disposed between the first polarizer and the second polarizer. The finder according to any one of [1] to

[10] .

[0016]

[12] The optical member is the finder according to any one of [1] to

[11] , which can control the polarization direction for a plurality of regions.

[0017]

[13] The polarization element is composed of a polarization beam splitter. The finder according to any one of [1] to

[12] .

[0018]

[14] The finder further includes a display device, and light emitted from the display device is incident on the first optical system. The finder according to any one of [1] to

[13] .

[0019]

[15] An imaging device including the finder according to any one of [1] to

[14] .

Brief Description of the Drawings

[0020] [Figure 1] Schematic Configuration Diagram Showing an Embodiment of HVF [Figure 2] Figure Showing the Change in Brightness of the Object Image Observed in OVF When the Transmittance is Changed [Figure 3] Figure Showing an Example When Controlling the Transmittance Partially [Figure 4] Figure Showing an Example of the Display of EVF [Figure 5] Figure Showing an Example of the Superimposed Display in OVF [Figure 6] Figure Showing an Example of the Display of OVF with the Transmittance Changed [Figure 7] Figure Showing an Example of the Arrangement of the Liquid Crystal Panel When the Objective Optical System Includes an Optical System with Negative Power [Figure 8] Figure Showing an Example of the Arrangement of the Liquid Crystal Panel When the Objective Optical System Includes an Optical System with Positive Power [Figure 9] Figure Showing an Example of the Configuration of HVF When Using a Resin Lens in the Objective Lens Group [Figure 10] Figure showing another example of a configuration for realizing the function of an electronically variable ND filter [Figure 11] Front view showing an embodiment of a digital camera [Figure 12] Rear perspective view of the digital camera shown in Fig. 11 [Figure 13] Block diagram showing the electrical configuration of a digital camera

Embodiments for Carrying Out the Invention

[0021] Hereinafter, preferred embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings.

[0022] [Finder] Here, the case where the present invention is applied to a hybrid viewfinder (HVF) will be described as an example.

[0023] As described above, the HVF is a finder having both functions of an optical viewfinder (OVF) and an electronic viewfinder (EVF). [[ID=3able]]

[0024] Fig. 1 is a schematic configuration diagram showing an embodiment of the HVF to which the present invention is applied.

[0025] [Overall Configuration of HVF] As shown in Fig. 1, the HFV1 includes an objective optical system 10, an eyepiece optical system 20, a finder display (display element) 30, a display element side optical system 40, a beam splitter 50, and the like.

[0026] [Objective Optical System] The objective optical system 10 includes a quarter-wave plate 11, a polarizer 12, a liquid crystal panel 13, and an objective lens group 14, etc. in order from the object side along the second optical axis L2. In the present embodiment, the objective optical system 10 is an example of a second optical system. Also, the second optical axis L2 is an example of the optical axis of the second optical system. [[ID=ble]]

[0027] The quarter-wave plate 11 converts linearly polarized light into circularly polarized light. An example of a scenario in which linearly polarized light is incident on the objective optical system 10 is when observing a liquid crystal display (LCD) as the subject. In such cases, the linearly polarized light is converted into circularly polarized light. This suppresses the change in the appearance of the optical viewfinder (OVF) depending on the orientation of the viewfinder (for example, the difference between vertical and horizontal imaging).

[0028] The quarter-wave plate 11 is placed, for example, in the viewfinder window of an imaging device equipped with an HVF1. The quarter-wave plate 11 can also be omitted.

[0029] The polarizer 12 transmits light polarized in a specific polarization direction. The polarization direction of the light transmitted by the polarizer 12 is defined as the first polarization direction. In this embodiment, the polarizer 12 is an example of a first polarizer.

[0030] The liquid crystal panel 13 controls the polarization direction of light transmitted through the polarizer 12. The liquid crystal panel 13 has a liquid crystal layer (not shown), and the liquid crystal layer controls the polarization direction of transmitted light. Specifically, the orientation of the liquid crystal molecules constituting the liquid crystal layer is electronically controlled to control the polarization direction of transmitted light. The liquid crystal panel 13 of this embodiment has a configuration that allows the polarization direction of transmitted light to be controlled for each region (pixel) divided in a matrix. That is, it has a configuration that allows the polarization direction to be controlled for each region in the region through which light is transmitted (a configuration that allows the polarization direction to be controlled for multiple regions). Note that the configuration of this type of liquid crystal panel itself is publicly known, so a detailed explanation is omitted. As an example, the liquid crystal panel 13 of this embodiment has a configuration in which an alignment film, transparent electrodes, and a transparent substrate are arranged with a liquid crystal layer in between, and the orientation of the liquid crystal molecules is controlled by applying a voltage between the transparent electrodes. That is, the polarization direction of transmitted light is controlled. In this embodiment, the liquid crystal panel is an example of an optical member and an example of a liquid crystal member.

[0031] As an example, in this embodiment, the polarizer 12 is positioned on the objective side of the liquid crystal panel 13 and has an integrated configuration. That is, the polarizer 12 and the liquid crystal panel 13 are constructed as a single unit.

[0032] The objective lens group 14 consists of at least one lens. As an example, in this embodiment, the objective lens group 14 is composed of two lenses: a first objective lens 14A and a second objective lens 14B.

[0033] [Ocular optical system] The eyepiece optical system 20 guides light from the objective optical system 10 and light from the display element-side optical system 40 to the observer's eye point EP via a beam splitter 50. The eyepiece optical system 20 includes an eyepiece lens group 21 and a cover glass 22, etc., arranged in order from the objective side along the second optical axis L2.

[0034] The eyepiece group 21 consists of at least one lens. As an example, in this embodiment, the eyepiece group 21 is composed of three lenses: a first eyepiece 21A, a second eyepiece 21B, and a third eyepiece 21C.

[0035] The cover glass 22 is positioned, for example, in the viewfinder eyepiece of an imaging device equipped with the HVF1.

[0036] [Viewfinder display] The viewfinder display 30 is an image display device within the viewfinder. As an example, in this embodiment, the viewfinder display 30 is composed of an organic light-emitting diode (OLED) display (OLED: Organic Light Emitting Diodes). However, the configuration of the viewfinder display 30 is not limited to this, and it can also be composed of, for example, a transmissive LCD with a backlight. The viewfinder display 30 is positioned on the first optical axis L1. The first optical axis L1 is an optical axis perpendicular to the first optical axis.

[0037] [Display element side optical system] The display element-side optical system 40 has at least one lens and guides light from the viewfinder display 30, which is the display element, to the beam splitter 50. As an example, in this embodiment, the display element-side optical system 40 is composed of three lenses. The three lenses are arranged along the first optical axis L1 in the order of first lens 40A, second lens 40B, and third lens 40C from the viewfinder display 30 side. In this embodiment, the display element-side optical system 40 is an example of the first optical system.

[0038] [Beam Splitter] The beam splitter 50 superimposes the light from the objective optical system 10 and the light from the display element-side optical system 40 and guides them to the eyepiece optical system 20. As an example, in this embodiment, the beam splitter 50 is composed of a polarizing beam splitter (PBS), and the superposition of light is performed using polarization. That is, the superposition of light is performed by selectively reflecting or transmitting only light with a specific polarization state. In particular, in this embodiment, the beam splitter 50 is composed of a cube-shaped dichroic polarizing beam splitter. The cube-shaped beam splitter 50 is composed of two right-angle prisms joined at their bevels, and the light is split by a thin film coating on the interface (joint surface). The two prisms are joined by an adhesive or optical contact. The beam splitter 50 in this embodiment has the function of reflecting S-polarized light and transmitting P-polarized light by the dichroic coating on the interface surface 50A. In this embodiment, the beam splitter 50 is an example of a polarizing element.

[0039] The beam splitter 50 is positioned at the intersection of the second optical axis L2 and the first optical axis L1. Furthermore, the beam splitter 50 is positioned with its interface 50A tilted at 45° relative to the second optical axis L2 and the first optical axis L1. The objective optical system 10 and the eyepiece optical system 20 are positioned on the second optical axis L2, flanking the beam splitter 50. Specifically, the objective optical system 10 is positioned on the objective side of the beam splitter 50, and the eyepiece optical system 20 is positioned on the eyepiece side (eyepoint side).

[0040] Light that has passed through the objective optical system 10 is guided to the eyepiece optical system 20 after the S-polarized component is reflected and the P-polarized component is transmitted through the beam splitter 50.

[0041] Meanwhile, the light emitted from the viewfinder display 30 and passing through the display element-side optical system 40 is guided to the eyepiece optical system 20 in the beam splitter 50, where the P-polarized component is transmitted and the S-polarized component is reflected.

[0042] As a result, in the beam splitter 50, the light from the objective optical system 10 and the light from the finder display 30 are superimposed and guided to the eyepiece optical system 20. This also makes it possible to observe an image in which the images of both are superimposed. In other words, it becomes possible to observe an image in which the screen display of the finder display 30 is superimposed on the object image from the OVF.

[0043] Here, the polarization direction of the P-polarized light transmitted by the beam splitter 50 is defined as the second polarization direction. The transmittance of light in the second polarization direction changes depending on the relationship between the polarization direction (first polarization direction) and the second polarization direction of the light transmitted by the polarizer 12 of the objective optical system 10, and is smallest when the two are orthogonal. When using an EVF, light in the second polarization direction becomes noise, so it is desirable that the transmittance of light in the second polarization direction be below a threshold value that does not become noise. In other words, it is most desirable that the polarization directions of the light transmitted by the polarizer 12 and the beam splitter 50 are orthogonal to each other. Therefore, if there were no liquid crystal panel 13, the light that passed through the objective optical system 10 would be reflected by the beam splitter 50. That is, it would not enter the eyepiece optical system 20. In this embodiment, orthogonality is an example of intersection.

[0044] [HVF Functions] In the HVF1 of this embodiment, configured as described above, the objective optical system 10, beam splitter 50, and eyepiece optical system 20 constitute an optical viewfinder (OVF). In addition, the finder display 30, display element-side optical system 40, beam splitter 50, and eyepiece optical system 20 constitute an electronic viewfinder (EVF).

[0045] Furthermore, in the HVF1 of this embodiment, the polarizer 12, the liquid crystal panel 13, and the beam splitter 50 constitute an electronically variable ND filter (ND: Neutral Density). That is, it functions as a variable ND filter in which the amount of light can be adjusted electronically. The mechanism is as follows.

[0046] When light is incident on the polarizer 12, only light polarized in a specific polarization direction (first polarization direction) is transmitted through the polarizer 12, while all other light is blocked.

[0047] Light transmitted through the polarizer 12 (light in the first polarization direction) has its polarization direction controlled by the liquid crystal panel 13 and is then incident on the beam splitter 50.

[0048] Here, if the polarization direction of the light incident on the beam splitter 50 matches the polarization direction of the light transmitted through the beam splitter 50, then all of the incident light will pass through the beam splitter 50. The polarization direction of the light transmitted through the beam splitter 50 is the direction of P polarization, which is the second polarization direction.

[0049] On the other hand, if the polarization direction of the light incident on the beam splitter 50 is perpendicular to the second polarization direction, all of the incident light will be blocked (reflected) by the beam splitter 50.

[0050] Furthermore, if the polarization direction of the light incident on the beam splitter 50 is tilted at 45° with respect to the second polarization direction, half of the incident light will pass through the beam splitter 50.

[0051] In this way, by controlling the polarization direction of the light incident on the beam splitter 50 with the liquid crystal panel 13, the amount of light transmitted through the beam splitter 50 can be adjusted. In other words, the light transmittance can be controlled.

[0052] Figure 2 shows the change in the brightness of the object image observed in the OVF when the transmittance is changed.

[0053] Figure 2(A) shows an example of an object image observed when transmittance is maximized.

[0054] The LCD panel 13 controls the polarization direction of light to the second polarization direction, thereby maximizing transmittance.

[0055] Figure 2(B) shows an example of an object image observed when the transmittance is set to 50%.

[0056] By tilting the polarization direction of light by 45° with respect to the second polarization direction using the liquid crystal panel 13, the transmittance becomes 50%.

[0057] Figure 2(C) shows an example of an object image observed when transmittance is minimized.

[0058] The liquid crystal panel 13 controls the polarization direction of light to a direction perpendicular to the second polarization direction, thereby minimizing transmittance. For example, in this embodiment, the transmittance is 0% (including a range that is considered to be approximately 0%). At minimum transmittance, light incident on the eyepiece optical system 20 is blocked.

[0059] In this way, the light transmittance can be controlled by controlling the polarization direction of light using the liquid crystal panel 13. This allows for adjustment of the brightness of the object image observed in the OVF.

[0060] Furthermore, light can be blocked when the transmittance is minimized. By blocking the light, the OVF is turned OFF. Therefore, the polarizer 12, liquid crystal panel 13, and beam splitter 50 function as an electronically variable ND filter and also as a shutter (viewfinder shutter).

[0061] As described above, the liquid crystal panel 13 of this embodiment can control the polarization direction of light transmitted to each matrix-divided region (pixel). Therefore, the transmittance can be partially controlled.

[0062] Figure 3 shows an example of a case where transmittance is partially controlled.

[0063] Figure 3(A) shows an example where the transmittance of a rectangular area in the lower right corner of the viewfinder frame is minimized. In this case, the object image in the OVF is observed with the lower right corner area obscured from light.

[0064] Figure 3(B) shows an example where the transmittance at the edges of the viewfinder frame is minimized. In this case, the object image in the OVF is obscured around the edges, and only the central part is observed.

[0065] [HVF display] As described above, HVF1 can be used as either an OVF or an EVF.

[0066] [When used as an EVF] When using the HVF1 as an EVF, the viewfinder shutter is closed. This means that the light transmission from the objective optical system 10 is minimized (transmission 0%). As a result, the light from the objective optical system 10 is blocked by the beam splitter 50.

[0067] With the viewfinder shutter closed, an image is displayed on the viewfinder display 30. Light emitted from the viewfinder display 30 enters the beam splitter 50 via the display element-side optical system 40. Of the light incident on the beam splitter 50, the S-polarized component is reflected by the beam splitter 50 and guided to the eyepiece optical system 20. The light guided to the eyepiece optical system 20 passes through the eyepiece optical system 20 and enters the eye point EP. As a result, the display on the viewfinder display 30 is observed at the eye point EP.

[0068] Figure 4 shows an example of an EVF display.

[0069] In the EVF, the image displayed on the viewfinder display 30 is observed. Figure 4(A) shows an example of displaying the live view image. Figure 4(B) shows an example of displaying predetermined imaging information in addition to the live view image.

[0070] [When used as OVF] When using the HVF1 as an OVF, the transmittance of light from the objective optical system 10 is set to a predetermined value (excluding 0%). For example, the transmittance is set to the maximum. This ensures that light from the objective optical system 10 is guided to the eyepiece optical system 20 with maximum transmittance. The light guided to the eyepiece optical system 20 passes through the eyepiece optical system 20 and enters the eye point EP. As a result, the object image of the subject is observed at the eye point EP.

[0071] When an image is displayed on the viewfinder display 30 while the OVF is in use, the display on the viewfinder display 30 is superimposed on the object image of the subject observed through the OVF. Specifically, when the viewfinder display 30 is displayed, the light from the viewfinder display 30 is superimposed on the light from the objective optical system 10 in the beam splitter 50 and incident on the eyepiece optical system 20. As a result, the display on the viewfinder display 30 is superimposed on the object image of the subject observed through the OVF.

[0072] Figure 5 shows an example of superimposed display in OVF.

[0073] Figure 5(A) shows an example of displaying an object image of a subject observed with an OVF (Optical Viewfinder) with a bright frame (BF) superimposed on it.

[0074] Figure 5(B) shows an example where predetermined imaging information is displayed in addition to the bright frame BF.

[0075] By controlling the liquid crystal panel 13 to control the light transmittance from the objective optical system 10, the brightness of the object image of the subject observed in the OVF can be adjusted.

[0076] The transmittance is adjusted manually or automatically. When adjusted automatically, a separate photometer is provided to measure the brightness (luminance) of the subject, and the adjustment is made based on the photometer's results. In this case, the brighter the subject, the lower the transmittance. That is, the transmittance is lowered in bright environments and increased in dark environments. This ensures good visibility regardless of ambient brightness.

[0077] It is preferable to adjust the brightness of the superimposed image according to the brightness of the subject. In other words, it is preferable to control the light output of the viewfinder display 30 according to the brightness of the subject.

[0078] Figure 6 shows an example of an OVF display with varying transmittance.

[0079] Figure 6(A) shows an example of the display when the transmittance is reduced, compared to the display shown in Figure 5(A). In this case, the OVF display becomes darker.

[0080] Figure 6(B) shows an example where an EVF display area (small window) S is provided within the viewfinder frame, and the EVF image (for example, a live view image) is displayed in the display area S. Figure 6(B) shows an example where the display area S is positioned in the lower right corner of the viewfinder frame. In this case, the transmittance of the display area S is set to the minimum (see Figure 3(A)). This blocks the light from the OVF in the display area S, improving the visibility of the image displayed in the display area S.

[0081] [Differential variations of the viewfinder] [Adjustment mechanism] In the HVF1 of the above embodiment, the polarization direction (second polarization direction) of the light (P-polarized light) transmitted by the beam splitter 50 is set to be perpendicular to the polarization direction (first polarization direction) of the light transmitted by the polarizer 12. Therefore, it is preferable that the relationship between the two can be finely adjusted after assembly. That is, it is preferable that the orientation of the transmission axis of the beam splitter 50 with respect to the transmission axis of the polarizer 12 can be adjusted relatively.

[0082] As an example, the beam splitter 50 is held so as to be rotatable around the second optical axis L2, and the tilt of the beam splitter 50 around the second optical axis L2 can be finely adjusted (a configuration in which the direction of the transmission axis can be adjusted around the optical axis). In this case, the beam splitter 50 is rotated around the second optical axis L2 to adjust the orientation of the transmission axis of the beam splitter 50 with respect to the transmission axis of the polarizer 12. After adjustment, the beam splitter 50 is fixed in place.

[0083] Alternatively, the polarizer 12 and the liquid crystal panel 13 may be held so as to be rotatable around the second optical axis L2, allowing for fine adjustment of the tilt of the polarizer 12 and the liquid crystal panel 13 around the second optical axis L2. Furthermore, both the polarizer 12 and the beam splitter 50 may be held so as to be rotatable, allowing for fine adjustment of the tilt of both around the second optical axis L2.

[0084] [Polarizers and beam splitters] In the HVF1 of the above embodiment, the polarizer 12, liquid crystal panel 13, and beam splitter 50 constitute an electronically variable ND filter. In this case, it is preferable that the combination of polarizer 12 and beam splitter 50 achieves a transmittance of 0%. That is, it is preferable that the amount of transmitted light be as close to zero as possible. This improves the function as a viewfinder shutter. As an example, a preferred transmittance is 0.1% or less. A more preferred transmittance is 0.05% or less, and even more preferably 0.01% or less. These transmittances are examples of threshold values.

[0085] One method to improve the performance of an electronically variable ND filter (a method to bring the transmittance closer to 0%) is to tune the dichroic coating of the beam splitter 50. In this case, for example, the dichroic coating is given the characteristic of transmitting only the polarization component that is perpendicular to the polarization direction of the light transmitted by the polarizer 12 (first polarization direction).

[0086] [LCD panel layout] The oblique incidence characteristics of the liquid crystal panel 13 change depending on its position. That is, the angle of incidence of light rays changes depending on the adjacent optical system. To improve the performance as an electronically variable ND filter, it is preferable that the angle of incidence of light to the liquid crystal panel 13 (liquid crystal layer) is small.

[0087] When the objective optical system 10 includes an optical system with negative power, the angle of the components emitted from the negative power optical system becomes gentler on the eyepiece side of the negative power optical system. Therefore, when the objective optical system 10 includes an optical system with negative power, it is preferable to place the liquid crystal panel 13 on the eyepiece side of the negative power optical system. This makes it possible to reduce the incident angle of the light rays incident on the liquid crystal panel 13 (liquid crystal layer), thereby improving the performance as an electronically variable ND filter.

[0088] Figure 7 shows an example of a liquid crystal panel arrangement when the objective optical system includes an optical system with negative power.

[0089] Figure 7 shows an example where the objective lens group 14 has negative power. In the example shown in Figure 7, the polarizer 12 and the liquid crystal panel 13 are placed between the objective lens group 14 and the beam splitter 50. This reduces the incident angle of the light rays incident on the liquid crystal panel 13, thereby improving the performance as an electronically variable ND filter. In this example, the objective lens group 14 is an example of an optical system with negative power.

[0090] On the other hand, if the objective optical system 10 includes an optical system with positive power, it is preferable to place the liquid crystal panel 13 on the objective side of the optical system with positive power. This makes it possible to reduce the incident angle of light rays incident on the liquid crystal panel 13 (liquid crystal layer), thereby improving the performance as an electronically variable ND filter.

[0091] Figure 8 shows an example of a liquid crystal panel arrangement when the objective optical system includes an optical system with positive power.

[0092] Figure 8 shows an example where the objective lens group 14 comprises a first objective lens 14A, a second objective lens 14B, and a third objective lens 14C arranged in order from the objective side along the second optical axis L2, with the first objective lens 14A having positive power. A polarizer 12 and a liquid crystal panel 13 are positioned on the objective side of the first objective lens 14A. This reduces the incident angle of the light rays incident on the liquid crystal panel 13, improving the performance as an electronically variable ND filter. In this example, the first objective lens 14A is an example of an optical system with positive power.

[0093] [Objective optical system] If the objective optical system 10 includes a resin optical element, birefringence may occur in that optical element. When birefringence occurs, the object image observed in the OVF deteriorates (becomes less clear).

[0094] When birefringence occurs due to polarization, the effect of birefringence can be suppressed by sandwiching the optical element causing the problem between two quarter-wave plates.

[0095] Figure 9 shows an example of the configuration of an HVF when resin lenses are used in the objective lens group.

[0096] As shown in Figure 9, the objective lens group 14 is arranged between the first quarter-wave plate 15A and the second quarter-wave plate 15B.

[0097] This makes it possible to suppress the effects of birefringence even when resin lenses are used in the objective lens group 14, and ensure good visibility in the OVF.

[0098] [Optical component that controls the polarization direction of light] In the above embodiment, the case in which a liquid crystal panel 13 (liquid crystal layer) is used as an optical element to control the polarization direction of light was described as an example, but the example of the optical element is not limited to this. Any element that can control the polarization direction of light is acceptable.

[0099] Furthermore, while the above embodiment provides a configuration that allows control of the polarization direction of light transmitted to each matrix-divided region (pixel), a configuration that controls the entire region collectively is also possible.

[0100] [Configuration of an electronically variable ND filter] In the above embodiment, the function of an electronically variable ND filter is realized by the polarizer 12, liquid crystal panel 13, and beam splitter 50, but the configuration for realizing the function of an electronically variable ND filter is not limited to this.

[0101] Figure 10 shows another example of a configuration that realizes the function of an electronically variable ND filter.

[0102] The HVF1 shown in Figure 10 has an additional polarizer 16 between the liquid crystal panel 13 and the beam splitter 50. More specifically, the polarizer 16 is positioned between the liquid crystal panel 13 and the objective lens group 14, and the liquid crystal panel 13 is positioned between the two polarizers 12 and 16. Hereinafter, the polarizer 12 positioned on the objective side of the liquid crystal panel 13 will be referred to as the first polarizer 12, and the polarizer 16 positioned on the eyepiece side will be referred to as the second polarizer 16, to distinguish between the two.

[0103] The first polarizer 12 transmits light polarized in the first polarization direction. On the other hand, the second polarizer 16 transmits light polarized in the second polarization direction. The first polarization direction and the second polarization direction are orthogonal to each other.

[0104] The polarization direction of the light transmitted by the second polarizer 16 (second polarization direction) is the same as the polarization direction of the light transmitted by the beam splitter 50 (P-polarized light) (second polarization direction).

[0105] In this example, the function of an electronically variable ND filter is realized by the first polarizer 12, the liquid crystal panel 13, and the second polarizer 16.

[0106] In addition, compared to the configuration of this example, the configuration of the above embodiment (configuration in Figure 1) can be simplified because the beam splitter 50 also functions as the second polarizer 16.

[0107] On the other hand, in this example, the beam splitter 50 does not necessarily have to be a polarizing beam splitter.

[0108] [Display device] In the above embodiment, an organic EL display is used as the display device, but the configuration of the display device is not limited to this. Other display devices such as LCDs, vacuum fluorescent displays (VFDs), and plasma display panels (PDPs) can also be used.

[0109] Furthermore, when using a device that outputs polarized light (for example, an LCD) as a display device, it is preferable to match the polarization direction of the light output by the display device with the polarization direction of the light reflected by the beam splitter 50.

[0110] [polarizing element] In the above embodiment, a prism-type beam splitter is used as the polarizing element for separating and superimposing light, but the configuration of the polarizing element is not limited to this. For example, a half-mirror or the like can also be used.

[0111] [Digital Camera] Figure 11 is a front view showing one embodiment of a digital camera to which the present invention is applied. Figure 12 is a rear perspective view of the digital camera shown in Figure 11.

[0112] This digital camera 100 is a so-called lens-integrated digital camera, having a configuration in which the imaging lens 102 is integrally assembled with the camera body 101. The digital camera 100 is an example of an imaging device.

[0113] As shown in Figures 1 and 2, the digital camera 100 comprises a camera body 101, an imaging lens 102, a hybrid viewfinder (HVF) 1, a rear monitor 103, and various operating components. The operating components include a power lever 111, a shutter button 112, an exposure compensation dial 113, a shutter speed dial 114, a viewfinder switching lever 115, a front command dial 116, a rear command dial 117, and the like.

[0114] The imaging lens 102 is located on the front of the camera body 101. The imaging lens 102 consists of a fixed focal length lens with a focus adjustment function.

[0115] In Figure 11, the HVF1 is located in the upper right corner (front upper right corner) of the camera body 101. The front of the camera body 101 is provided with the viewfinder window 1A of the HVF1, and the rear is provided with the viewfinder eyepiece 1B of the HVF1. Also, adjacent to the viewfinder eyepiece 1B, the rear of the camera body 101 is provided with an eye sensor 118. The eye sensor 118 is a sensor that detects the proximity of the eye to the viewfinder eyepiece 1B (a sensor that detects the use of the HVF1).

[0116] The rear monitor 103 is located on the back of the camera body 101. The rear monitor 103 is composed of, for example, an LCD display.

[0117] Among the operating components provided on the camera body 101, the viewfinder switching lever 115 is a lever that switches the mode of the HVF1. The viewfinder switching lever 115 is located on the front of the camera body 101. The viewfinder switching lever 115 is operated by swinging it to switch the mode of the HVF1. Specifically, each time the viewfinder switching lever 115 is swung, the OVF and EVF of the HVF1 switch alternately.

[0118] [Electrical configuration of a digital camera] Figure 13 is a block diagram showing the electrical configuration of a digital camera.

[0119] As shown in Figure 13, the digital camera 100 includes an imaging lens 102, a lens drive unit 120, an image sensor 121, a digital signal processing unit 130, an AF detection unit 131, a photometering unit 132, a memory card interface unit (I / F: interface) 133, a memory card 134, a rear monitor 103, a monitor driver 135, a communication interface unit (I / F: interface) 136, a flash memory 137, an operation unit 140, a viewfinder display 30, a display driver 30A, a liquid crystal panel 13, a liquid crystal driver 13A, and a camera control unit 150, etc.

[0120] [Imaging lens and lens drive unit] The imaging lens 102 is composed of multiple lenses. The imaging lens 102 has a focusing mechanism, and the focus is adjusted by moving some of its lenses (focus lenses) 102f back and forth along the imaging optical axis Z. The imaging lens 102 also has an aperture 102i, and the amount of light is adjusted by adjusting the aperture size of the aperture 102i. The aperture 102i is composed of, for example, an iris aperture.

[0121] The lens drive unit 120 includes a focus lens drive unit 120f for driving the focus lens 102f, and an aperture drive unit 120i for driving the aperture 102i.

[0122] The focus lens drive unit 120f moves the focus lens 102f back and forth along the imaging optical axis Z. The focus lens drive unit 120f includes an actuator such as a motor and its drive circuit. The focus lens drive unit 120f is controlled by the camera control unit 150. The camera control unit 150 controls the focus lens drive unit 120f to control the movement of the focus lens 102f.

[0123] The aperture drive unit 120i expands and contracts the opening of the aperture 102i. The aperture drive unit 120i includes an actuator such as a motor and its drive circuit. The aperture drive unit 120i is controlled by the camera control unit 150. The camera control unit 150 controls the aperture drive unit 120i to control the amount of the aperture 102i opening.

[0124] [Image sensor] The image sensor 121 converts an optical image into an electrical signal. The image sensor 121 can be, for example, a CMOS (Complementary Metal Oxide Semiconductor) type image sensor or a CCD (Charged Coupled Device) type image sensor having a predetermined color filter array (e.g., a Bayer array). As an example, the digital camera 100 of this embodiment uses a CMOS type color image sensor equipped with a drive unit, an ADC (Analog to Digital Converter), and a signal processing unit. In this case, the image sensor 121 operates by being driven by its built-in drive unit. Furthermore, the signal from each pixel is converted into a digital signal by the built-in ADC. In addition, the signal from each pixel is subjected to processing such as correlated double sampling, gain processing, and correction processing as needed by the built-in signal processing unit. These signal processing operations may be performed before the conversion of each pixel's signal into a digital signal, or they may be performed after the conversion into a digital signal.

[0125] [Digital signal processing unit] The digital signal processing unit 130 receives the signal output from the image sensor 121 and performs predetermined signal processing (for example, grayscale conversion processing, white balance correction processing, gamma correction processing, syncing processing, YC conversion processing, etc.) to generate image data.

[0126] [AF detection unit] The AF detection unit 131 takes in the signal output from the image sensor 121 and generates evaluation value (focus evaluation value) information necessary for AF (Auto Focus) control.

[0127] [Photometry section] The photometering unit 132 takes in the signal output from the image sensor 121 and detects the brightness (luminance) of the subject.

[0128] [Memory card interface section and memory card] The memory card interface unit 133 reads and writes data to the memory card 134 inserted in the card slot.

[0129] [Rear monitor and monitor driver] The rear monitor 103 is used for playback of captured images and as a settings screen when various settings are configured. Furthermore, the rear monitor 103 can be used as a live view monitor at the user's discretion. That is, the image captured by the image sensor 121 is displayed on the rear monitor 103 in real time.

[0130] The display on the rear monitor 103 is controlled by the camera control unit 150. The camera control unit 150 controls the display on the rear monitor 103 via the monitor driver 135.

[0131] [Communication Interface Section] The communication interface unit 136 communicates with external devices in a specified communication format. The communication is controlled by the camera control unit 150.

[0132] [Flash memory] The flash memory 137 stores various data necessary for controlling the digital camera 100, etc.

[0133] [Operation section] The operation unit 140 outputs a signal to the camera control unit 150 corresponding to the operation of the operating member provided on the camera body 101.

[0134] [Finder display and display driver] The viewfinder display 30 provided in the HVF1 is controlled by the camera control unit 150. The camera control unit 150 controls the display of the viewfinder display 30 via the display driver 30A. This control also includes light intensity control.

[0135] [LCD panel and LCD driver] The liquid crystal panel 13 provided in the HVF1 is controlled by the camera control unit 150. The camera control unit 150 controls the driving of the liquid crystal panel 13 via the liquid crystal driver 13A.

[0136] By controlling the drive of the liquid crystal panel 13, the polarization direction of the light passing through the liquid crystal panel 13 is controlled, and the transmittance of the optical viewfinder (OVF) is controlled. In addition, the viewfinder shutter is opened and closed.

[0137] [Camera Control Unit] The camera control unit 150 is a control unit that provides overall control over the operation of the digital camera 100. The camera control unit 150 is composed of a computer equipped with, for example, a CPU (Central Processing Unit) as a processor, and RAM (Random Access Memory) and ROM (Read Only Memory) as memory. In other words, the computer functions as the camera control unit 150 by executing a predetermined program.

[0138] [How digital cameras work] This section explains the operation of digital camera 1, focusing on the operation of the HVF1.

[0139] The user captures images of the subject using the HVF1 and / or the rear monitor 103. Which is used depends on the view mode setting. The view mode setting is performed, for example, on a designated settings screen.

[0140] The view modes include a mode that uses only the HVF1, a mode that uses only the rear monitor 103, and a mode that uses both the HVF1 and the rear monitor 103. The mode that uses both the HVF1 and the rear monitor 103 includes a mode in which the display is automatically switched by the eye sensor 118 and a mode in which the display is always shown on both. In addition, the mode that uses only the HVF1 includes a mode in which the display is automatically turned on and off by the eye sensor 118 and a mode in which the display is always on.

[0141] If the HVF1 is selected as the view mode, the user will use the HVF1 to capture images of the subject.

[0142] As described above, the HVF1 of this embodiment can be used by switching between OVF and EVF. Switching between OVF and EVF is performed by the viewfinder switching lever 115.

[0143] When the EVF is selected, the live view is displayed on the HVF1 (see Figure 4). In this case, the viewfinder shutter is closed, and the live view is displayed on the viewfinder display 30. This causes the HVF1 to function as an EVF. The user uses the HVF1, which is functioning as an EVF, to check the imaging area, focus status, etc.

[0144] Here, the operation of closing the viewfinder shutter is performed by the liquid crystal panel 13. That is, the liquid crystal panel 13 controls the polarization direction of the transmitted light, and sets the transmittance of light from the objective optical system 10 to the minimum (the transmittance is set to 0% or nearly 0%). As a result, the light from the objective optical system 10 is blocked, and the viewfinder shutter is closed.

[0145] On the other hand, if the OVF is selected, the viewfinder shutter opens. This allows the object image of the subject to be observed through the OVF from the viewfinder eyepiece 1B (see Figure 5).

[0146] When the optical viewfinder (OVF) is selected, the bright frame (BF) is displayed on the viewfinder display 30. Additionally, imaging information is displayed as needed. This allows the information displayed on the viewfinder display 30 to be superimposed on the object image from the OVF.

[0147] Here, the operation to open the viewfinder shutter is performed by the liquid crystal panel 13. In other words, the liquid crystal panel 13 controls the polarization direction of the transmitted light, increasing the transmittance of light from the objective optical system 10. As a result, light from the objective optical system 10 is guided to the eyepiece optical system 20, and the viewfinder shutter opens.

[0148] When the optical viewfinder (OVF) is selected, the amount of light in the viewfinder display 30 is controlled based on the metering result (subject brightness) of the metering unit 132 in order to improve the visibility of the display in the viewfinder. In other words, the amount of light is controlled according to the metering result.

[0149] Furthermore, the transmittance of light from the objective optical system 10 is controlled based on the photometric results from the photometering unit 132. The transmittance is controlled by the liquid crystal panel 13. In this case, the brighter the subject, the lower the transmittance. That is, the transmittance is lowered in bright environments and increased in dark environments. This ensures good visibility regardless of the ambient brightness.

[0150] Furthermore, it is preferable to control the light intensity of the viewfinder display 30 in conjunction with changes in transmittance. Specifically, it is preferable to control the light intensity so that the ratio of the light intensity of the object image of the subject observed in the OVF to the display on the viewfinder display 30 superimposed on that object image remains constant at all times. This ensures good visibility of the display in the viewfinder.

[0151] [Comparative Examples of Imaging Devices] In the above embodiment, the present invention was described as being applied to a digital camera with an integrated lens, but the application of the present invention is not limited to this. It can also be applied to digital cameras with interchangeable lenses.

[0152] The HVF1 may be configured as an external viewfinder that can be attached to and detached from the camera body.

[0153] [Note] In this specification, the term “same” includes not only the meaning of completely identical, but also the meaning of “approximately the same,” which includes tolerances for design and manufacturing.

[0154] Furthermore, in this specification, the term "orthogonal" includes not only the meaning of perfect orthogonality, but also the meaning of "approximately orthogonal," which includes tolerances for design and manufacturing. [Explanation of Symbols]

[0155] 1A...Viewfinder window 1B... Finder eyepiece 10…Objective optical system 11...1 / 4 wavelength plate 12…Polarizer (First polarizer) 13… LCD panel 13A... LCD driver 14…Objective lens group 14A…First objective lens 14B…Second objective lens 14C…Third objective lens 15A…1 / 4 wavelength plate 15B…1 / 4 wavelength plate 16…Polarizer (Second Polarizer) 20…Eyepiece optical system 21… Eyepiece group 21A...First eyepiece 21B...Second eyepiece 21C...Third eyepiece 22… Cover glass 30…Viewfinder display 30A…Display driver 40…Display element side optical system 40A…First lens 40B...Second lens 40C…Third lens 50... Beam Splitter 50A…Boundary surface 100... Digital camera 101...Camera body 102…IMAGING lens 102f... Focus lens 102i... Aperture 103... Rear monitor 111... Power lever 112... Shutter button 113... Exposure compensation dial 114... Shutter speed dial 115... Viewfinder selector lever 116…Front command dial 117... Rear command dial 118... Eye sensor 120...Lens drive unit 120f...Focus lens drive unit 120i... Aperture drive unit 121...Image sensor 130... Digital signal processing unit 131...AF detection unit 132…Photometering section 133...Memory card interface section 134…Memory card 135... Monitor Driver 136...Communication Interface Section 137…Flash memory 140...Operation unit 150...Camera control unit BF...Bright Frame EP... Eye Point L1…1st optical axis L2…Second optical axis S…display area Z...imaging optical axis

Claims

1. The first optical system and, A second optical system includes a first polarizer that transmits light in a first polarization direction, and an optical element that controls the polarization direction of the light transmitted through the first polarizer. A polarizing element that reflects at least a portion of the light that has passed through the first optical system and transmits light in the second polarization direction from the light that has passed through the second optical system, It has a viewfinder.

2. The optical component is a liquid crystal component. The finder according to claim 1.

3. The first polarizer and the polarizing element are related such that the transmittance of light in the second polarization direction is below a threshold. The finder according to claim 1.

4. The first polarizer and the polarizing element have a relationship in which the first polarization direction and the second polarization direction intersect. The finder according to claim 1.

5. The polarizing element is capable of relatively adjusting the direction of its transmission axis with respect to the transmission axis of the first polarizer. A finder according to any one of claims 1 to 4.

6. The polarizing element can rotate around the optical axis of the second optical system to adjust the direction of the transmission axis of the polarizing element with respect to the transmission axis of the first polarizer. The finder according to claim 5.

7. The second optical system includes an optical system with negative power, The first polarizer and the optical element are positioned closer to the eyepiece than the negative power optical system. A finder according to any one of claims 1 to 4.

8. The XL2 optical system includes an optical system with positive power. The first polarizer and the optical element are positioned on the objective side of the optical system having positive power. A finder according to any one of claims 1 to 4.

9. The second optical system further includes a first quarter-wave plate and a second quarter-wave plate, wherein at least one optical element is disposed between the first quarter-wave plate and the second quarter-wave plate. A finder according to any one of claims 1 to 4.

10. The optical element positioned between the first quarter-wave plate and the second quarter-wave plate is a resin optical element. The finder according to claim 9.

11. The second optical system further includes a second polarizer that transmits light in the second polarization direction, and the optical member is disposed between the first polarizer and the second polarizer. A finder according to any one of claims 1 to 4.

12. The optical element is capable of controlling the polarization direction for multiple regions. A finder according to any one of claims 1 to 4.

13. The polarizing element is composed of a polarizing beam splitter. A finder according to any one of claims 1 to 4.

14. It also has a display device, Light emitted from the display device is incident on the first optical system. A finder according to any one of claims 1 to 4.

15. An imaging device comprising a viewfinder according to any one of claims 1 to 4.

Images