JPS6234141A - In-finder display device - Google Patents

Abstract

PURPOSE:To display an alarming pattern with the brightness of a visible field retained by installing in an optical path of a finder plural gratings composed of an interface made of two substances roughly perpendicular to said optical path using an optically anisotropic material for either one of said two substances and controlling the optical axis direction. CONSTITUTION:Anisotropic substances 1 and 1' having different optical axis directions, a transparent optical member 2, a transparent electrode 3, a transparent space 4 and a transparent heater are provided. The optical axis directions of polarized components 7 and 7' orthogonally intersecting due to an incident light 6 and those of the anisotropic substances 1 and 1' are illustrated. The optical axis of the 1st-layered anisotropic substance 1 points a grating groove direction 8, while that of the 2nd- layered substance 1' points a direction 8'. The anisotropic substances 1 and 1' change their optical axis directions due to the impression of an electric field, and accordingly the refraction factor felt by the incident light 6 changes. In a static state without the impression of an electric field, the polarized component 7' of the incident light 6 in the 1st layer feels the abnormal refraction of the anisotropic substance 1, while the polarized component 7 feels the normal refraction ratio of the substance 1.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field The present invention relates to a display device, and particularly to a display device that displays various information at the time of photographing in a finder of a photographing device such as a camera or a video camera.

(2) Prior Art Conventionally, when displaying predetermined photographic information in the finder of a photographing device such as a camera or a video camera, an LED or liquid crystal placed outside the photographic field of view has been used. However, with this type of mechanism, there is a possibility that the display warning of inappropriate exposure conditions may be overlooked, and furthermore, it is impossible to display the in-focus area or appropriate exposure area within the photographic field of view. - In view of the above-mentioned drawbacks, the applicant and others have proposed displaying a liquid crystal display or the like overlapping the visual field. For example, JP-A EV+ 52-11062
6 utilizes a TN (twisted-nematic) liquid crystal display. However, since this type of display normally uses a polarized plate, a maximum light utilization efficiency of only about 50% can be achieved. Furthermore, JP-A No. 58-62626 uses a GH (guess)-host) type liquid crystal display, and although a polarizing plate is not required, the light utilization efficiency is reduced due to the constant presence of light absorption by dye molecules. Ta.

Therefore, in the conventional system, although the photographing field circle display device in the finder is highly useful, it has the drawback that sufficient brightness cannot be obtained within the finder.

[3) Summary of the invention The object of the present invention is to eliminate the above-mentioned conventional drawbacks.

To provide an in-finder display device that can be placed in a position that covers almost the entire luminous flux in the finder optical path, and that can provide a clear display at any location while maintaining the brightness in the finder at all times. .

In order to achieve the above object, an in-finder display device according to the present invention is an in-finder display device that displays shooting information, patterns, etc. in the finder of a camera.
A plurality of gratings made of interfaces of two materials are provided in the optical path in the finder almost perpendicularly to the optical path, one of the two materials is made of an optically anisotropic material, and Controlling the optical axis direction of anisotropic materials・1
t, in the first state, the optical axis directions of the plurality of gratings are all aligned so that all the subject light is transmitted, and in the second state, 1) the plurality of gratings in item 11 overlap It is characterized by changing the direction of the optical axis of a predetermined portion to block at least part of the object light and displaying photographic information, patterns, etc.

The optically anisotropic substance is an electric field, a magnetic field, or heat.

A substance whose optical axis can be changed by pressure, light, etc., or a substance whose refractive index can be changed by =11, such as liquid crystal or electro-optic crystal, i.e. PLZ.
T, LiNbO3゜LiTaO3, TiO2, PMMA
, CCu4KDP, ADP, ZnO, BaTiO3.

B i 12 S i 020 , B a 2 N
a N b 5015 , M nBi , EuO,
CS2, Gd2(MOO4)3.

Bi 4Ti 30t2, CuCJl, GaAs
, ZnTe, As2Se3. Se, AsGe5eS.

DKDP, MNA, mNA, UREA, 7o~
Examples include resist, nematic liquid crystal, cholesteric liquid crystal, smectic liquid crystal, and ferroelectric liquid crystal. In particular, liquid crystal is a suitable material because it is inexpensive and easy to control.

In addition to displaying a monochrome pattern by transmitting and blocking (diffraction) the subject light, this display device can also perform color display using a color filter or the like, color display using the spectral transmittance characteristics of a grating, etc.

Furthermore, methods for creating the above-mentioned grating include a method using a resist, a method using photolithography and dry etching, a replica method using a thermosetting resin or an ultraviolet curable resin, a cutting method using a ruling engine, or an embossing method. There are various methods such as

(4) Example Fig. 1, Fig. 214. FIG. 3 is a basic configuration diagram of a display element used in a display device according to the present invention, in which 1 and 1' are anisotropic materials whose optical axes differ in direction, 2 is a transparent optical member, 3 is a transparent electrode, and 4 is a The transparent spacer 5 is a transparent heater.

FIG. 1 is a basic configuration diagram of an electric field control type display element, in which two gratings are formed within one element. In the device shown in FIG. 1(A), the transparent optical member 2 has a triangular grating, and anisotropic substances 1.1' are arranged above and below with an L-plate transparent spacer 4 in between. The electrode 3 is formed along the grating of the transparent optical member 2. In the device shown in FIG. The anisotropic material l is placed facing the transparent optical member 2 side to be
, 1' are arranged below. Note that the transparent electrode 3 is provided on each transparent optical member 2. In the device shown in FIG. 1(C), transparent optical members 2 having flat transparent electrodes 3 are placed facing each other, and a transparent spacer 4 having gratings on both sides is disposed between the transparent molds [3]. U-tropic substances 1 and 1' are placed in the gap above and below with the gap between them.

FIG. 2 is a basic configuration diagram of a thermally controlled display element, and as can be seen from the diagram, the basic structure is almost the same as that in FIG. 1. However, in FIG. 2(A), a transparent heater 5 is placed in place of the spacer 4 to separate the anisotropic substances 1 and 1' into J-bottom, and FIG.
), a transparent heater 5 is provided around the transparent electrode 3 in FIG. 1(B).

Furthermore, FIG. 3 shows a display device in which one grating is formed in two stages, and the anisotropic materials 1.1' used in each device have optical axes in different directions. In each element, a grating is formed on a transparent optical member 2, and an electric field is applied by a transparent electrode 3 provided on the member 2 to control the optical axis direction of the anisotropic substances 1, 1'.

The operating principle of the display element described above will be described below. Since all of the display elements described above have almost the same principle of operation, the element shown in FIG. 1(A) will be explained here as an example. Note that light having an arbitrary plane of polarization, such as natural light, can be considered by dividing it into two predetermined orthogonal polarization components.

FIG. 4 is a diagram illustrating the operating principle of the display element 1-.

Reference numeral 6 indicates the incident light, 7.7' indicates the polarization component orthogonal to If in each incident light 6, and 8 and 8' indicate the optical axis direction of the anisotropic material 1.1'. Note that the same members as in FIG. 1(A) are designated by the same numbers.

In FIG. 4, the optical axis of the anisotropic material 1 in the first layer is directed toward the grating groove direction 8, and the anisotropic material 1 in the second layer 11 is oriented in the grating groove direction 8.
The optical axis of ' is directed in the grating arrangement direction 8'. Here, the optical axis direction of the anisotropic substances 1 and 1' changes by applying an electric field, and the refractive index perceived by the incident light 6 changes.

In the first state IE, that is, in the static state with no electric field applied, the first state IE is
The polarized light component 7' of the incident light 6 in the layer senses the extraordinary refraction ne of the anisotropic material 11, and the polarized light component 7 senses the ordinary refractive index no of the anisotropic material 1. or.

In the second layer, the polarized light component 7' of the incident light 6 senses the ordinary refractive index no' of the anisotropic material 1', and the polarized light component 7' senses the extraordinary refractive index ne' of the anisotropic material 1'. feel.

Here, the refractive index of the transparent optical member 2 forming the first layer grating is ng, the height of the grating is T,
If the refractive index of the transparent optical member 2 forming the second layer grating is ng', the height of the grating is T', and the wavelength of the incident light is input, then the first and second layer gratings Diffraction efficiency of zero-order transmitted diffracted light η0゜η0′
are expressed by the following equations (1) and (2). I can do it.

Δ nT y) o = sin c 2 (w-) --
-----(1) Input Δn'T'ηo'= sin c 2 (π-)
-----(2)λ From the above equation, when Δn=o, ηo=1. When Δn'=0, ηo'=1, and Δn T = m input (m= 1,
2, 3, -----), η0=0, Δn'T'=m
The number of inputs (m = 1, 2, 3, --1-) is ηo
We can see that ′=0. That is, the 1st J? +In my eyes,
If no=ng or ne=ngt-is satisfied,
Either one of the polarized light components 7 and 7' passes through, and the other is modulated according to equation (1). In addition, the second layer [1, n
If o'=ng' or ne'=ng' is satisfied, either one of the polarized light components 7 and 7' will pass through.

The other is modulated according to equation (2).Next, when applying an electric field to the anisotropic materials 1 and 1', the optical axis directions of the anisotropic materials 1 and 1' change, and accordingly, the incident The refractive index experienced by the polarized components 7 and 7' of the light 6 also changes. That is, depending on the change in Δn, the first and second layers are subjected to modulation according to equations (1) and (2).

For example, when using the same liquid crystal for anisotropic materials 1 and 1', ne=ne', no=no', and the initial condition is n.
g=ng ′=no, T=T'lne-ngl urn T=m
If λ, the diffraction efficiency of the zero-order transmitted diffracted light at the entrance of the first layer and the second layer is both i? A tingling sensation expressed by formula (1) is produced.

Further, it is assumed that the refractive index of the spacer 4 is approximately equal to ng. At this time, in a static state, the polarized light component 7 of the incident light 6 passes through the first layer, and the polarized light component 7' is ηo=
0, and the zero-order transmitted diffraction light is not emitted, but all the higher-order diffraction light is emitted. In addition, in the second layer, the polarized light component 7 becomes η0 = 0 according to equation (1), and the zero-order transmitted light diffracted light is not emitted, but all of the polarized light component 7 is emitted as higher-order diffracted light, and the polarized light component 7 is 7' passes through as high-order diffracted light. Therefore, no light passes through this element and is emitted in the zero-order direction.

Next, a predetermined electric field is applied to direct the optical axes (orientation directions) of liquid crystals 1 and 1' perpendicularly to the grating plane (plane including arrows 8 and 8'), that is, in the direction of propagation of the incident light 6. case,
Since the polarized light components 7 and 7' of the incident light 6 sense the ordinary refractive index n□ of the liquid crystal 1°1' in the first and second layers, they pass through this element and become zero-order transmitted light. Emits light.

Therefore, depending on whether or not an electric field is applied, light having an arbitrary plane of polarization, such as natural light, can be modulated without using a polarizing plate or the like.

In the display elements shown in FIGS. 1 to 4, the gratings in each layer are arranged in the same direction, but the gratings forming each layer can be arranged in any direction as long as it does not interfere with the modulation effect. It's okay. Further, although the bipedal grating has a triangular wave shape, it may also have a rectangular or sinusoidal shape as shown in FIG. 5, and the desired function can be achieved regardless of the shape of the grating. However, when the shapes of the gratings are different, the formula for the diffraction efficiency as shown in the above formula (1) will be different. For example, for a rectangular grating, the formula for the diffraction efficiency will be as shown in formula (3) below.

l AnT ηo= −(1+ cos (2π□) )−−−
(3) 2 people In addition, it does not matter if multiple gratings have different shapes individually, and the shape of the grating should be decided by taking into account ease of manufacture, specifications, etc. - Figure 6 shows a triangular shape. Visible wavelength range of zero-order transmitted light in this device when using a wavy or rectangular grating: 400 to 70
It shows the spectral transmittance characteristics at 0 nm. Here, the vertical axis is the transmittance η0, the horizontal axis is the wavelength λ, and 9.9' in the figure represents the characteristics of the triangular and rectangular gratings when light is transmitted, respectively.
Reference numeral 110' indicates the characteristics of the triangular wave grating and the rectangular grating when light is blocked.As shown in Figure 0, the rectangular grating has strong wavelength selectivity, and the triangular wave grating has almost no wavelength selectivity.

Therefore, as described above, the grating shape is selected in consideration of the purpose of use of the imaging device, the system surrounding the display device, and the like.

An example of a method for manufacturing the display element shown in FIG. 1(A) will be described below.

FIG. 7 shows the manufacturing process of the display element shown in FIG. 1(A), in which reference numeral 11 denotes a liquid crystal, and members similar to those in FIG. 1 are denoted by the same numbers.

Transparent PBMA resin substrate 2 (37X26X1mm', n
g=1.56) (1') Both sides are transparent surfaces, Figure 7 (
As shown in A), a triangular wave grating with a pitch of 3 μm and a depth of 2.4 mm was formed on the entire surface of one side of the substrate 2 by embossing. Subsequently, an ITO film 3 having a thickness of 1,000 wafers was formed on the grating substrate 2.

Using the method similar to 4-Distribution, another cover plate having a display pattern as shown in FIG. 7CB) was prepared on the transparent PHMA substrate 2. Next, as shown by the arrow in Figure 7(C), the front and back sides were subjected to orientation treatment in directions perpendicular to each other, and the thickness was 5 g.
A Teflon spacer 4 is sandwiched between the two transparent PBMA substrates 2, and a positive dielectric liquid crystal MBBA (n
o=1.56, ne=1.786) 11 was filled to produce a display element as shown in FIG. 7(D).

An example in which a display device produced by the method described above is applied to a camera finder will be described below.

FIG. 8 is a diagram showing an example of the display device in the finder according to the present invention, where 12 is the display device, 13 is a focusing plate with a Fresnel lens, 14 is a condenser lens, 15 is a pentaprism, 16 is an eyepiece lens, and 17 is a focusing plate with a Fresnel lens. Showing a reflector.

Reflection! The subject light guided into the finder by the display device 12, the focusing plate 13, and the condenser lens 1
4, it becomes an erect image by a pentaprism 15, and enters the photographer's eye through an eyepiece 16. Here, during the period when a rectangular alternating current electric field is applied between two electrodes in the display device 12, the entire field of view in the finder is in a light-transmitting state, and the object image is clearly seen through the eyepiece lens 16. I can do things. On the other hand, when displaying warnings such as underexposure warnings and focus status, the electric field of the warning display part that is patterned according to signals from the exposure and focus detection devices is set to O.
The display portion can be displayed in a predetermined state. An example of this is shown in Figure 59. In the figure, 18 is 4 in the center.
A transparent optical member having a semi-transparent mirror with a 5° inclined surface has the function of sending a portion of the light that has passed through the photographing lens to the exposure 1, 1 detection channel or the light receiving end 21 for focus detection. 22 is an exposure amount detection circuit or focus detection circuit that receives and analyzes the output of the light receiving element 21, and 23 is a voltage generation circuit that receives the detection signal from the detection circuit 22 and outputs it to the present display device. 12.

An example of the display is shown in Figure 10. In Figure 10, (a) shows an underexposure warning for one period, (b) shows an overexposure warning, (c) shows an appropriate exposure, (d) shows the front focus state, and (e) is after pin state,
(f) represents focus. As described above, display within the photographing field frame can be performed with high contrast without impairing the brightness of the image, and when no display is performed, there is no effect on observation of the subject image.

” In the two-legged embodiment, the display device 12 is connected to the condenser lens 1.
4 and the focusing plate 13, but it is clear that it may be placed near the eyepiece lens 16 depending on the system configuration within the finder. Additionally, since this display device utilizes the diffraction phenomenon caused by the grating, it is also effective to take measures to remove the diffracted light that becomes flare light, such as providing a fiber plate or the like on the light beam output side of this display device. It is.

Next, a method for creating another configuration example of the display device according to the present invention will be described. Rectangular wavy cratings with a pitch of 3 μm and a depth of 1.8 μm as shown in FIG. 11 are formed on both sides of the transparent PMMMA resin film 4 using a rectangular wavy hot rolling roller. Here, the rectangular wave-like gratings are created so that their arrangement directions are perpendicular to each other on the front and back sides of the film 4.

Next, two BK7 boards (37X26X1mm', ng
= 1.49), both sides of which are transparent planes, one of which is covered with ITO, and the other with a pattern as shown in Figure 7 (B).
1l! 2 was formed into a film to a thickness of 100 mm. Next, 2
Two BK7 substrates are placed facing each other with their ITO film surfaces facing each other, and a film 4 having a crating is sandwiched therebetween. Next, the gap between the grating of film 4 and both BK7 substrates is filled with a positive electrode. A conductive liquid crystal ZLI-2141-000 (manufactured by Mel/y, no=149°ne=1.64) was filled, and the liquid crystal was forcibly aligned in the groove direction by the grooves of the grating.

Therefore, the alignment directions of the liquid crystals filled in the gap between the upper and lower gratings via the film 4 are perpendicular to each other.

Although the display devices in the two embodiments described above are provided with patterns to be displayed created in advance within the device, it is of course possible to use matrix-driven display devices for this viewfinder display device, and the camera If matrix driving is performed in combination with various detection devices, the in-focus area display and appropriate exposure area indicator will also be i7+ capable, and various display formats can be obtained.

Further, the structure of the display device can also be a two-stage structure as shown in FIG. 3, and it is obvious that various device structures can be adopted depending on the structure of the finder. Furthermore, in the above embodiment, an example in which liquid crystal was applied as an optically anisotropic substance was shown, but anisotropic substances are not limited to liquid crystals, and electro-optic effects such as electro-optic crystals, thermo-optics etc. Various anisotropic materials having magneto-optical effects can be applied.

(5) As described in detail, the in-finder display device according to the present invention does not require a polarizing plate because it does not have polarization characteristics, and can transmit subject light with high transmittance in a normal state of 7g. The device is capable of displaying photographic information and the like with high contrast. Therefore, the apparatus becomes capable of displaying a warning pattern, displaying an area, etc. over the entire surface of the viewfinder, both inside and outside the field of view frame, while maintaining the configuration and brightness of the field of view.

[Brief explanation of the drawing]

1, 2, and 3 are basic configuration diagrams of a display element used in a display device according to the present invention. FIG. 4 is a diagram illustrating the operating principle of the display element shown in FIGS. 1 to '5F) 3, and FIG. 5 is a diagram showing another example of the shape of the grating. FIG. 6 is a diagram showing the spectral transmittance characteristics in the visible wavelength range of triangular wave gratings and rectangular wave gratings, and shows the spectral transmittance characteristics when light is transmitted and when light is blocked. FIG. 7 is a diagram showing an example of the manufacturing process of the display element shown in FIG. 1(A). FIG. 8 is a diagram showing an example of an in-finder display device according to the present invention. Figure 9 shows the exposure detection device or focus detection device. A diagram showing an example of a combination of the present devices. FIG. 10 is a diagram showing an example of a display pattern by the present display device. FIG. 11 is a diagram showing an example of a spacer used in a display element. 1, 1'----An optically anisotropic material in which the directions of one optical axis are different from each other. 2 -------One transparent optical member 3------One transparent electrode 4---One transparent spacer 5---One transparent heater 6---One incident light 7, 7'- ----Polarized light component 8, 8' perpendicular to T of the single incident light---Direction of the optical axis of the anisotropic material 9
----- Spectral transmittance characteristics of a triangular wave grating when one light is transmitted 9' ----- Spectral transmittance characteristics of a rectangular wave grating when one light is transmitted 10-1 to --- Triangular when light is blocked Spectral transmittance characteristics of wavy grating 10' ----- Spectral transmittance characteristics of rectangular wavy grating when blocking one light 11 ------- Liquid crystal 12 --- Display device 13 ------ - Focusing plate 14 -------Condenser lens 15 -------Penta prism 16 ----m=Eyepiece 17 ----One reflecting mirror 18 --------One 45° in the center Transparent optical member 19 having a semi-transparent mirror with an inclined surface --- One lens 20 --- One mirror 21 --- One detection light-receiving element 22 --- One detection circuit

Claims (1)

[Claims] (1) In an in-finder display device that displays shooting information, patterns, etc. in the finder of a camera, a plurality of gratings made of interfaces of two substances are placed in the optical path in the finder almost perpendicular to the optical path. and one of the two materials is composed of an optically anisotropic material, and by controlling the optical axis direction of the anisotropic material, in the first state, the plurality of gratings In the second state, the directions of the optical axes of the plurality of gratings are made to be approximately the same so that all the object light is transmitted, and in the second state, the directions of the optical axes of predetermined overlapping portions of the plurality of gratings are made different so that at least one part of the object light is transmitted. A display device in the viewfinder that is characterized by blocking the area and displaying shooting information, patterns, etc.