WO2010140493A1 - Image display device having function which permits light from object to be observed to pass therethrough - Google Patents

Abstract

Provided is an image display device having a function which permits light from an object to be observed to pass therethrough. The image display device comprises a display element which includes a pair of transparent substrates with electrodes and a liquid crystal layer held between the pair of substrates with electrodes, said liquid crystal layer being capable of assuming a light transmission state and a light scattering state, said light transmission state being established when no voltage is applied and said light scattering state being established when a voltage is applied; a light source which irradiates light substantially parallel with a surface of the liquid crystal layer onto the liquid crystal layer; and a timing control circuit which controls the state of the display element in association with the state of emission of light from the light source under the presence of external light. The image display device includes a light non-emission frame in which only a display color corresponding to the external light is obtained by bringing the display element into the light scattering state and a light emission frame in which a display color corresponding to the color of the light of the light source is obtained by bringing the display element into the light scattering state in synchronization with the emission of colored light from the light source. The timing control circuit brings the corresponding display element into the light scattering state in association with at least a part of a non-emission period provided in the light emission frame to thereby obtain a display color corresponding to the external light.

Description

Image display device having function of transmitting light from object to be observed

The present invention enables an observer to view an object located on the back surface of a display element through the display element, and to display information provided to the observer. The present invention relates to an image display device having a light transmission function.

Some camera finder devices include a dispersive (diffusion) liquid crystal display panel (see, for example, Patent Documents 1 and 2). FIG. 20 is a cross-sectional view showing a part of a camera including a viewfinder device described in Patent Literatures 1 and 2. As shown in FIG. 20, a mirror 311 that reflects external light incident through a lens 321 provided inside the lens barrel 320 is provided inside the camera body 300. The optical path of the light reflected by the mirror 311 is changed by the prism 313, passes through the eyepiece lens 314, and reaches the outside of the fluoroscopic window 315.

Inside the camera main body 300, a liquid crystal display panel 312 driven by a drive circuit 316 is provided in the middle of the optical path of the light reflected by the mirror 311. The liquid crystal display panel 312 is configured such that a liquid crystal element is sandwiched between a pair of transparent substrates with electrodes. When a voltage is applied between the substrates, the liquid crystal display panel 312 enters a light transmissive state, and a light scattering state is obtained when no voltage is applied. Present.

A photographer who photographs an object to be observed using a camera photographs while looking through the fluoroscopic window 315, and the mode is operated by the photographer operating a switch (not shown) provided in the camera body 300. Settings can be made. A CPU (not shown) provided in the camera main body 300 controls the drive circuit 316 so that a voltage is not applied between electrodes in a predetermined display target area of the liquid crystal display panel 312 according to a set mode. Control. As a result, as illustrated in the explanatory diagram of FIG. 21, a predetermined sign is displayed in the display target area. FIG. 21 shows an example in which a sign 310 indicating a focus area is displayed. In the liquid crystal display panel 312, in a region other than the display region of the sign 310, the voltage is continuously applied, and the liquid crystal display panel 312 is in a light transmission state. Therefore, the photographer can view the object to be observed and the sign 310 from the perspective window 315.

Japanese Unexamined Patent Publication No. 2004-212792 Japanese Unexamined Patent Publication No. 2000-75393

However, the finder apparatus using the liquid crystal display panel 312 has the following problems. First, since it is necessary to apply a voltage between the substrates in order to bring the liquid crystal display panel 312 into a light transmission state, the power consumption of the camera increases. In general, since an electric circuit provided in the camera is driven by a battery, the usable period of the battery is shortened. In addition, when displaying the camera provided with the finder device using the liquid crystal display panel 312 so that the user can contact the storefront of the store, the battery is consumed if the power is turned on. Therefore, it will be displayed with the power off. Then, when the user looks into the see-through window 315 of the camera, nothing can be visually recognized, and the user may be distrusted with the quality of the camera.

Further, in the liquid crystal display panel 312, an electrode for displaying a sign (in the example shown in FIG. 21, each side of a substantially rectangular shape indicating a focus area) is provided in a portion where the sign 310 is displayed. A wiring pattern connected to the electrode for displaying the signs is provided.
Therefore, when the voltage application to the sign display electrode is stopped and the sign display area is set in the light scattering state, the wiring pattern area is also recognized in the light scattering state. That is, the appearance of the display surface of the image display device is deteriorated. In FIG. 21, a broken line portion indicates a wiring pattern.

Also, when the light source is turned on, there is a possibility that the entire display panel is colored by the light source color (hereinafter referred to as flare) due to the influence of the light source.

Accordingly, an object of the present invention is to provide an image display device having a function of transmitting light from an object to be observed with good display surface appearance (hereinafter referred to as a light transmission function) while reducing power consumption. To do.

An image display device having a function of transmitting light from an object to be observed according to the present invention is sandwiched between a pair of transparent substrates with electrodes and the pair of substrates with electrodes, and can take a light transmission state and a light scattering state. A display element that includes a liquid crystal layer and is in a light-transmitting state when no voltage is applied and is in a light-scattering state when a voltage is applied; a light source that causes light substantially parallel to the surface of the liquid crystal layer to be incident on the liquid crystal layer; And a timing control circuit for causing at least a part of the display surface of the display element to be in a light scattering state or a light transmission state in conjunction with a state of light emission to the liquid crystal layer in the light source. The light non-emission frame and the light source have a light emission frame. In the non-emission frame, at least a part of the display surface of the display element is in a light-scattering state to display according to the external light. Color only In the light emission frame, in synchronism with the color of the light source, at least part of the surface of the display element is caused to be in a light scattering state to obtain a display color corresponding to the light source color, and the timing control circuit includes In conjunction with at least a part of a predetermined light non-emission period provided in the light emission frame, at least a part of the display surface of the display element is made to be in a light scattering state so that a display color corresponding to the external light is obtained. It is characterized by obtaining.

In a frame in which the light source does not emit light, at least a part of the display surface of the display element may be in a light scattering state in all periods in the frame to obtain a display color corresponding to external light.

The light source emits one light source color or sequentially emits two or more light source colors.

According to the present invention, it is possible to provide an image display device that can reduce power consumption and has a function of transmitting light from an object to be observed having a good display surface appearance.

FIG. 1 is a schematic external view showing an image display device according to the present invention. FIG. 2 is a schematic cross-sectional view showing a display element according to the present invention. 3A to 3E are explanatory views illustrating curable compounds that can be used for display elements. FIG. 4 is a schematic cross-sectional view showing an application example of the image display device according to the present invention. FIG. 5 is an explanatory diagram illustrating an example of display on the image display apparatus. FIG. 6 is a schematic diagram showing the relationship between the drive of the display element and the light source in the image display apparatus. FIG. 7 is a block diagram illustrating a configuration example of a driving circuit for driving the display element. FIG. 8 is a schematic diagram showing the relationship between the drive of the display element and the light source in the image display apparatus. FIG. 9 is a schematic diagram showing the relationship between the drive of the display element and the light source in the image display apparatus. FIG. 10 is a schematic diagram illustrating the relationship between the drive of the display element and the light source in the image display apparatus. FIGS. 11A to 11C are explanatory diagrams for explaining the configuration and operation of the image display apparatus when one light source is used. 12A to 12F are explanatory diagrams for explaining the operation of the light guide section. FIG. 13 is a block diagram showing another configuration example of a drive circuit for driving the display element. FIG. 14 is a schematic diagram illustrating the relationship between the drive of the display element and the light source in the image display apparatus according to the first embodiment. FIG. 15 is a schematic diagram illustrating a relationship between display element driving and a light source in the image display apparatus according to the second embodiment. FIG. 16 is a schematic diagram illustrating the relationship between the drive of the display element and the light source in the image display apparatus according to the third embodiment. FIG. 17 is a schematic diagram illustrating the relationship between the drive of the display element and the light source in the image display apparatus according to the fourth embodiment. FIG. 18 is a schematic diagram illustrating the relationship between the drive of the display element and the light source in the image display apparatus according to the fifth embodiment. FIG. 19 is a schematic diagram showing the relationship between the drive of the display element and the light source in an image display device as a comparative example. FIG. 20 is a schematic cross-sectional view showing a part of a camera including a viewfinder device. FIG. 21 is an explanatory diagram showing an example of the display of the conventional example.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, a display method used in the image display apparatus according to the present invention will be described. The image display device according to the present invention uses a field sequential color system that obtains a color display by combining a liquid crystal display panel and a light source whose emission color is switched between red, blue, and green in the presence of external light. In the field sequential color system, an image corresponding to each emission color is sequentially displayed on a liquid crystal panel and driven.
Therefore, the response of the liquid crystal panel needs to be sufficiently fast.

In the field sequential color method, for example, it is necessary to display one color in 1/3 time of one field. Therefore, for example, when displaying 60 fields / second, the time available for display is about 5 ms (milliseconds). ) Therefore, the liquid crystal itself is required to have a response time shorter than 5 ms. As a liquid crystal capable of realizing a high-speed response, a ferroelectric liquid crystal, an antiferroelectric liquid crystal, a narrow gap nematic liquid crystal, an OCB mode liquid crystal, and the like are known.

However, since the polarizing plate is used in the display element using those liquid crystals, there is a disadvantage that the transmittance is low, and there is a problem that visibility is lowered when the viewer looks behind through the display element. . Therefore, the image display device according to the present invention is a liquid crystal display element that can take a light transmission state and a light scattering state as described below, and is light from a light transmission state at room temperature (for example, 25 ° C.). A liquid crystal display element that can make the response time required for switching to the scattering state and switching from the light scattering state to the light transmission state shorter than 5 ms is used. Although the response speed of the liquid crystal generally decreases at a low temperature, it is possible to cope with a temperature range suitable for the application by performing temperature compensation.

FIG. 1 is a schematic external view showing an example of an image display device according to the present invention. As shown in FIG. 1, the image display device 10 includes a light source 2 that can be controlled in a time-sharing manner, such as an LED, and a driving voltage of the display element (electro-optical element) 1 and a light source 2 are A lighting voltage is supplied. The display element 1 can switch the liquid crystal layer between a transparent state and a light scattering state depending on whether or not a voltage is applied to the transparent electrode based on an external signal or the like. And a figure can be displayed.

Further, when light is supplied from the light source 2 to the liquid crystal layer of the display element 1, the scattering portion of the liquid crystal layer scatters the light and is recognized brightly by the observer 3. By changing the color of the light of the light source 2 to an arbitrary color, it is possible to cause the character or figure to have an arbitrary color. The light source 2 is provided at the edge portion of the display element 1 and makes light incident on the liquid crystal layer. In addition, it is preferable that the light guide part which diffuses light between the light source 2 and the display element 1 is provided. In the present invention, transparent means a state where the light transmittance is 50% or more, preferably 80% or more. In the case of transparency, the observer 3 can visually recognize the object to be observed through the display element 1. That is, the image display apparatus 10 has a function of transmitting light from the object to be observed (light transmission function).

FIG. 2 is a schematic cross-sectional view illustrating a configuration example of the display element 1 in the image display device 10.
In FIG. 2, transparent electrodes 102 and 107 are provided on opposing surfaces of the pair of substrates 101 and 108. Further, alignment films 103 and 106 are provided on the inner side. A liquid crystal layer 104 containing liquid crystal and having a thickness controlled by a spacer (not shown) is sandwiched between the alignment films 103 and 106. Then, the liquid crystal layer 104 is sealed by the seal layer 105.

The material of the substrates 101 and 108 is not particularly limited as long as transparency can be secured. As the substrates 101 and 108, glass substrates or plastic substrates can be used. Moreover, the shape of the display element 1 does not need to be planar, and may be curved.

Further, as the transparent electrodes 102 and 107 provided on the substrates 101 and 108, a transparent electrode material such as a metal oxide such as ITO (indium oxide-tin oxide) can be used. Hereinafter, the substrates 101 and 108 provided with the transparent electrodes 102 and 107 are referred to as substrates with electrodes.

The liquid crystal layer 104 capable of taking a light transmission state and a light scattering state is a composition containing a liquid crystal and a curable compound soluble in the liquid crystal (hereinafter, an uncured composition) between a pair of transparent substrates with electrodes. A liquid crystal layer formed as a liquid crystal / polymer composite by curing a curable compound using means such as heat, ultraviolet rays, or an electron beam is preferable. Hereinafter, a liquid crystal composed of a composite of such a liquid crystal and a polymer is also referred to as a liquid crystal / polymer composite.

The liquid crystal used in the liquid crystal / polymer composite may have either positive or negative dielectric anisotropy, but in order to shorten the response time required for switching between the light transmission state and the light scattering state, the viscosity of the liquid crystal is low, Furthermore, it is preferable to use a liquid crystal having negative dielectric anisotropy. As the liquid crystal, a non-curable compound is used. Moreover, the curable compound may have liquid crystallinity.

In the case where a liquid crystal having a negative dielectric anisotropy is used, in the substrate with electrodes, a treatment is performed so that the pretilt angle of liquid crystal molecules is 60 degrees or more with respect to the substrate surface on the side in contact with the liquid crystal layer 104. When applied, orientation defects can be reduced and transparency is improved, which is preferable. In this case, the rubbing process may not be performed. The pretilt angle is more preferably 70 degrees or more. The pretilt angle is defined as 90 degrees in the direction perpendicular to the substrate surface.

The liquid crystal constituting the liquid crystal / polymer composite forming the liquid crystal layer 104 can be appropriately selected from known liquid crystals. By using a substrate with an electrode that can control the pretilt angle of the uncured composition by the alignment films 103 and 106, a liquid crystal having a positive dielectric anisotropy and a liquid crystal having a negative dielectric anisotropy can be used. However, a liquid crystal having negative dielectric anisotropy is preferable in terms of higher transparency and response speed. The alignment film can also be rubbed. In order to reduce the driving voltage, it is preferable that the absolute value of dielectric anisotropy is large.

Further, the curable compound constituting the liquid crystal / polymer composite preferably has transparency.
Furthermore, it is preferable that the liquid crystal and the curable compound are separated so that only the liquid crystal responds when a voltage is applied after curing, because the driving voltage can be lowered.

In the present invention, among the curable compounds that can be dissolved in the liquid crystal, the alignment state of the mixture of the liquid crystal and the curable compound when uncured can be controlled, and high transparency can be maintained when cured. A curable compound is used.

Examples of the curable compound include a compound of formula (1) and a compound of formula (2).
A ¹ —O— (R ¹ ) _m —O—Z—O— (R ² ) _n O—A ² (1)
A ^3- (OR ³ ) _o -O-Z'-O- (R ⁴ O) _p -A ⁴ (2)

Here, each of A ¹ , A ² , A ³ , and A ⁴ is independently an acryloyl group, methacryloyl group, glycidyl group, or allyl group that becomes a curing site, and R ¹ , R ² , R ³ , R Each of ⁴ is independently an alkylene group having 2 to 6 carbon atoms, each of Z and Z ′ is independently a divalent mesogen structure, and each of m, n, o, and p Is independently an integer from 1 to 10. Here, “independently” means that the combination is arbitrary and any combination is possible.

Molecular motion including R ¹ , R ² , R ³ , R ⁴ between the mesogenic structures Z, Z ′ and the cured sites A ¹ , A ² , A ³ , A ^{4 in the} formulas (1) and (2) By introducing a highly functional oxyalkylene structure, the molecular mobility of the cured site can be improved during the curing process during curing, and it can be sufficiently cured in a short time.

The curing sites A ¹ , A ² , A ³ , and A ⁴ in the formulas (1) and (2) may be any functional group as long as they can be photocured or thermally cured. It is preferable that it is an acryloyl group and a methacryloyl group suitable for photocuring.

The carbon number of R ¹ , R ² , R ³ and R ^{4 in} the formulas (1) and (2) is preferably 1 to 6 from the viewpoint of molecular mobility, and an ethylene group having 2 carbon atoms and 3 carbon atoms. The propylene group is more preferable.

Examples of the mesogen structure parts Z and Z ′ in the formulas (1) and (2) include polyphenylene groups in which 1,4-phenylene groups are linked. A part or all of the 1,4-phenylene group may be substituted with a 1,4-cyclohexylene group. In addition, some or all of the hydrogen atoms of the 1,4-phenylene group or substituted 1,4-cyclohexylene group may be substituted with alkyl groups having 1 to 2 carbon atoms, halogen atoms, carboxyl groups, alkoxycarbonyl groups, or the like. It may be substituted with a group.

As preferred mesogen structure parts Z and Z ′, a biphenylene group in which two 1,4-phenylene groups are linked (hereinafter, a biphenylene group in which two 1,4-phenylene groups are linked is also referred to as a 4,4-biphenylene group). Examples thereof include three linked terphenylene groups and those in which 1 to 4 of these hydrogen atoms are substituted with an alkyl group having 1 to 2 carbon atoms, a fluorine atom, a chlorine atom or a carboxyl group. Most preferred is a 4,4-biphenylene group having no substituent. All the bonds between the 1,4-phenylene group or 1,4-cyclohexylene group constituting the mesogen structure may be a single bond or any of the following bonds.

M, n, o, and p in Formula (1) and Formula (2) are each independently preferably from 1 to 10, and more preferably from 1 to 4. This is because if it is too large, the compatibility with the liquid crystal is lowered and the transparency of the electro-optical element after curing is lowered.

FIG. 3 shows examples of curable compounds that can be used in the present invention. The composition containing a liquid crystal and a curable compound may contain a plurality of curable compounds including the curable compounds represented by the formulas (1) and (2). For example, when the composition contains a plurality of curable compounds having different m, n, o, and p in the formulas (1) and (2), the compatibility with the liquid crystal may be improved.

The composition containing the liquid crystal and the curable compound may contain a curing catalyst. In the case of photocuring, a photopolymerization initiator generally used for photocurable resins such as benzoin ether, acetophenone, and phosphine oxide can be used. In the case of thermosetting, a curing catalyst such as peroxide, thiol, amine, or acid anhydride can be used depending on the type of curing site, and if necessary, a curing aid such as amines can be added. It can also be used.

The content of the curing catalyst is preferably 20% by mass or less of the curable compound to be contained, and more preferably 0.1 to 5% by mass when a high molecular weight or high specific resistance of the cured resin is required after curing. .

In the uncured composition, the total amount of the curable compound is preferably 0.1 to 20% by mass with respect to the liquid crystal composition. If it is less than 0.1% by mass, the liquid crystal phase cannot be divided into domain structures having an effective shape by the cured product, and desired transmission-scattering characteristics cannot be obtained. On the other hand, when it exceeds 20% by mass, the haze value in the transmissive state tends to increase as in the case of the conventional liquid crystal / cured material composite element. More preferably, the content of the cured product in the liquid crystal composition is 0.5 to 15% by mass, the scattering intensity in the light scattering state is high, and the voltage value at which transmission-scattering is switched can be reduced. .

As a processing method for aligning liquid crystal molecules so that the pretilt angle is 60 degrees or more with respect to the substrate surface, there is a method using a vertical alignment agent. As a method using a vertical alignment agent, for example, a method using a surfactant, a method of treating a substrate interface with a silane coupling agent containing an alkyl group or a fluoroalkyl group, or SE1211 or JSR manufactured by Nissan Chemical Industries, Ltd. There is a method using a commercially available vertical alignment agent such as JALS-682-R3 manufactured by the company. In order to create a state in which the liquid crystal molecules are tilted in an arbitrary direction from the vertical alignment state, any known method may be adopted. The vertical alignment agent may be rubbed. Alternatively, a method may be employed in which a slit is provided in the transparent electrodes 102 and 107 or a triangular prism is disposed on the electrodes 102 and 107 so that the voltage is applied obliquely to the substrates 101 and 108. Further, it is not necessary to use means for tilting the liquid crystal molecules in a specific direction.

The thickness of the liquid crystal layer 104 between the two substrates 101 and 108 can be defined by a spacer or the like. The thickness is preferably 1 to 50 μm, more preferably 3 to 30 μm. If the thickness of the liquid crystal layer 104 is too thin, the contrast is lowered, and if it is too thick, the driving voltage tends to increase, which is not preferable in many cases.

As the sealing layer 105, any known material can be used as long as it is a highly transparent resin. If a highly transparent resin is used, the display element becomes transparent over the entire surface, and the state that characters and figures appear to float in the air is emphasized. For example, when a glass substrate is used as the substrates 101 and 108, a transparent glass floats in the air if an epoxy resin or an acrylic resin having a refractive index close to that of the glass is used. realizable. Moreover, in the case of a usage method in which the seal layer is usually not visually recognized by an observer, the seal layer does not need to be transparent.

The image display device 10 manufactured as described above can realize a very high response speed with a response time between the light transmission state and the light scattering state of the display pixel being shorter than 5 ms at least near room temperature. In addition, the viewing angle dependency is better than that of the conventional scattering transmission mode by the dispersion type liquid crystal element, and a very good light transmission state can be obtained even when viewed obliquely. For example, when a composite containing a curable compound having the above composition and a liquid crystal is used, there is almost no haze even when viewed at an angle of 40 degrees from the vertical.

As the size of the display element 1, any size can be used, including one with a diagonal length of about 1 cm to about 3 m.

In the image display device 10, a plurality of display elements 1 may be used. Further, the upper and lower substrates 101 and 108 may be fixed in order to increase the impact resistance against the display element 1.

It is preferable to provide an antireflection film or an ultraviolet blocking film on the front and back surfaces of the display element 1. For example, by applying AR coating (low reflection coating) made of a dielectric multilayer film such as SiO ₂ or TiO _{2 on} the front and back of the display element 1, reflection of external light on the substrate surface can be reduced, and contrast can be reduced. Can be further improved.

As the light source 2, a light source capable of time-sharing control such as an LED is used. However, when a field sequential color method is realized, for example, a method of sequentially lighting red, green, and blue light sources may be used. A method of sequentially changing the color of the color by combining a color filter with respect to light may be used.

FIG. 4 is an explanatory diagram showing an application example of the image display device 10 according to the present invention. In the example shown in FIG. 4, an image display device 10 (in FIG. 4, only the display element 1 in the image display device 10 is shown) is applied to a finder device of a camera. As shown in FIG. 4, the display element 1 is driven by the drive circuit 20, but the other components are the same as those shown in FIG. However, unlike the example shown in FIG. 20, when a voltage is applied between the substrates in the image display device 10, the liquid crystal layer enters a light scattering state, and exhibits a light transmission state when no voltage is applied.
Therefore, the user of the camera can visually recognize the object to be observed through the see-through window 315 even when no voltage is applied. When a part of the liquid crystal layer is in a light scattering state, external light that has entered the light scattering state display portion from the lens 321 passes through the light scattering state display portion after being reflected by the prism 313 as the optical path changes. Since a part or all of the light is not incident on the eyepiece lens 314, the display portion in the light scattering state is dark to the viewer, that is, visually recognized as black.

This eliminates the need to apply a voltage between the substrates in order to place the liquid crystal display panel 312 in a light transmissive state, thereby reducing the power consumption of the camera. Since the electric circuit provided in the camera is driven by a battery, the usable period of the battery is shortened. Further, even when the camera provided with the finder device using the liquid crystal display panel 312 is displayed so that the user can contact the storefront of the store, the camera can be displayed with the power turned on. The user can check the quality of the camera sufficiently because the user can sufficiently see the image when looking through the see-through window 315. Further, since the voltage application to the sign display electrode is not stopped and the sign display area is not put into the light scattering state, the display surface of the image display device looks good.

Further, as shown in the enlarged view of the image display device 10 in FIG. 4, light guide portions (light guide plates) 4 having substantially the same thickness as the display elements 1 are formed on the left and right edges (edge portions) of the display element 1. The light from the light source 2 is incident on the liquid crystal layer of the display element 1 through the light guide 4. The light guide 4 is formed of an acrylic plate as an example. The light incident on the liquid crystal layer is light substantially parallel to the surface of the liquid crystal layer (surface parallel to the substrate surface), and the incident light leaks from the display surface of the display element 1 when the liquid crystal layer is in a light transmission state. Reduce the number of exits. If the incident light is more completely parallel to the surface of the liquid crystal layer, this light leakage will be less.

In the example shown in FIG. 4, an LED light source that emits red (R), green (G), and blue (B) light is used as the light source 2. The light source 2 causes a light source color to be incident on the liquid crystal layer from the side of the display element 1 via the light guide 4 so as to be substantially parallel to the surface of the liquid crystal layer. Although the light emission of the LED has a straight traveling property, when the light guide unit 4 is provided, when the light enters the light guide unit 4, the surface reflection is repeated in the light guide unit 4 and spreads over a wide range. Incident to the layer.

FIG. 5 is an explanatory diagram showing a display example of the display element 1. In the example shown in FIG. 5, the display element 1 displays a sign 7 indicating the remaining battery level, a sign 8 indicating the shootable range, and a sign 9 indicating the shutter speed. In the example shown in FIG. 5, the shutter speed indicates 1/1000 second. An area other than the area where the signs 7, 8, and 9 are displayed, in particular, an area surrounded by the sign 8 indicating the imageable range is a transparent area.

Next, the relationship between the light source 2 and the drive of the display element 1 in the field sequential color system used in the image display device 10 of the present invention will be described with reference to the timing chart of FIG.

In the display element 1 shown in FIG. 5, white color is developed in the area of the label 8, or red color is developed in the area of the label 7 so that it is visually recognized as black in the observation through the eyepiece 314 when the light source is not lit. Assume that you want to As the light source 2, light sources of three colors of red, green, and blue are used. As shown in FIG. 6, the three colors are sequentially lit, and the cycle in which all of RGB is lit once is defined as one frame. If the area of the marker 8 is in the light scattering state for all of the R lighting time, the G lighting time, and the B lighting time, the area of the marker 8 is colored white. Further, if the area of the sign 8 is in a light scattering state during the period in which the light source 2 is not turned on, the area of the sign 8 is visually recognized as black due to scattering of external light when viewed through the eyepiece 314. Is done. If the area of the marker 7 is in the light scattering state only during the R lighting time and is in the light transmitting state during the G and B lighting times, the area of the marker 7 is colored red. As described above, when displaying in light source color or black on at least a part of the display element 1, each portion to be displayed is in a light scattering state in conjunction with the lighting state of the light source in the presence of external light. Alternatively, the light transmission state may be controlled.

The period of one frame corresponding to the lighting period of the three color light sources is preferably (1/15) seconds or less. That is, it is preferable that the frame frequency corresponding to the lighting frequency of the three color light sources is 15 Hz or more. This is because if it is less than 15 Hz, flicker may be visually recognized. More preferably, the frame frequency is 30 Hz or more, and more preferably 60 Hz or more.

The display element 1 manufactured as described above is in a light scattering state when a predetermined voltage (for example, 60 V) is applied to the liquid crystal layer 104 as a liquid crystal layer capable of taking a light transmission state and a light scattering state. When the voltage is not applied to the liquid crystal layer 104, the light transmission state is obtained. Accordingly, in FIG. 6, the scattered signal ON corresponds to a predetermined voltage being applied between the transparent electrodes 102 and 107, and the transparent signal ON is that the potential difference between the transparent electrodes 102 and 107 is 0V. Corresponds to the state.

Hereinafter, a signal for generating the light source ON and light source OFF timing shown in FIG. 6, that is, a signal for instructing each light source to rise and fall of the light source ON and the light source OFF is referred to as a switching signal.

FIG. 7 is a block diagram illustrating a configuration example of a drive circuit that drives the display element 1. Note that the drive circuit shown in FIG. 7 corresponds to the drive circuit 20 shown in FIG. In the example shown in FIG. 7, one transparent electrode 1021 for driving the area of the sign 8 (hereinafter also referred to as the display section 8) and the area of the sign 7 (hereinafter also referred to as the display section 7) are driven. In response to an instruction from the timing control circuit 201, a driving voltage is applied to one transparent electrode 1022 and one transparent electrode 1023 for driving a region of the transparent electrode 1022 and the label 9 (hereinafter also referred to as the display unit 9). The electrode driving circuit 203, the other transparent electrode 1071 for driving the area of the display unit 8, the other transparent electrode 1072 for driving the area of the display unit 7, and the other transparent electrode 1072 for driving the area of the display unit 9 An electrode driving circuit 204 that applies a driving voltage to the transparent electrode 1073 according to an instruction from the timing control circuit 201 is provided. A drive voltage is supplied from the voltage generation circuit 202 to the electrode drive circuit 203 and the electrode drive circuit 204. The voltage generation circuit 202 receives power supply from, for example, a battery attached to the camera.

The transparent electrodes 1021, 1022, and 1023 correspond to the transparent electrode 102 shown in FIG. 2, and the transparent electrodes 1071, 1072, and 1073 correspond to the transparent electrode 107 shown in FIG. In FIG. 7, only the lead-out portions of the transparent electrodes 1021, 1022, 1023, 1071, 1072, and 1073 are shown.

Further, in FIG. 7, the areas of the display units 7, 8, and 9 are shown as areas surrounded by broken lines, but actually, as illustrated in FIG. 5 among the areas surrounded by broken lines. A transparent electrode made of ITO or the like is provided at a portion where display is performed, and extends from the transparent electrodes 1021, 1022, 1023 and 1071, 1072, 1073 shown in FIG. That is, the wiring pattern from the transparent electrodes 1021, 1022, and 1023 and the transparent electrodes 1071, 1072, and 1073 shown in FIG. 7 to the electrode portions provided in the portion shown in FIG. Are formed on the front and back surfaces of the display element 1.

The timing control circuit 201 turns on the red light source (red LED) 31, the green light source (green LED) 32, and the blue light source (blue LED) 33 in the light source 2, for example, at the timing illustrated in FIG. That is, a switching signal is given to the red light source 31, the green light source 32, and the blue light source 33. The display unit 8 is formed of a plurality of segments, and gives an instruction to the electrode drive circuit 203 so that a drive voltage (for example, −30 V) is applied to the transparent electrode 1021 corresponding to the common electrode when the scattered signal is ON. An instruction is given to the electrode drive circuit 204 so that a drive voltage (for example, +30 V) is applied to the transparent electrode 1071 connected to the segment to be formed according to display data.

FIG. 13 is a block diagram showing another configuration example of a drive circuit that drives the display element 1.
In this example, temperature compensation is performed by the temperature sensor 205 associated with the timing control circuit, particularly at low temperatures. For example, light source ON / OFF timing modulation is performed according to a parameter for each temperature.

The drive voltage applied to the transparent electrode 1021 and the transparent electrode 1071 is, for example, ± 30 V. However, the drive voltage of the transparent electrode 1021 and the drive voltage of the transparent electrode 1071 may be changed between positive and negative at a predetermined timing. preferable. However, since high frequency can be one of the factors that increase power consumption, it is preferable to set the balance appropriately.

The display units 7 and 9 are formed of a plurality of segments, and the timing control circuit 201 drives the transparent electrodes 1022 and 1023 corresponding to the common electrodes in the state of the scattered signal ON illustrated in FIG. 6 (for example, −30 V). Is applied to the electrode drive circuit 203 so that the drive voltage (for example, +30 V) is applied to the transparent electrodes 1072 and 1073 connected to the segment to be displayed. .

In the display element 1, when a TFT element is used as a drive element, the viewer can visually recognize the TFT element when the scattering signal is OFF and the display element 1 is in a transparent state. There is sex. However, in the present embodiment, the display element 1 does not include an active element such as a TFT element, and is statically driven. Therefore, in the transparent state, an element that should not be visually recognized is not visually recognized.

The color of RGB of the light source can be switched almost simultaneously with the input of the switching signal. However, the display units 7, 8, and 9 have the input of scattered signals and transparent signals (specifically, transparent electrodes 1021, 1022, 1023, 1071, It is not possible to change it immediately upon application of drive voltage to 1072 and 1073 or erasure of drive voltage. This is because there is a delay in the response of the display element. If the light scattering state is maintained other than the desired light source color, color mixture occurs and causes color deterioration. Therefore, it is necessary to avoid the situation where the light scattering state is maintained other than the desired light source color. is there. Therefore, it is preferable to shift the timing of the switching signal input to the light source and the timing of the signal input (drive voltage application start or drive voltage erasure) to the display units 7, 8 and 9.

For example, as shown in FIG. 8, the timing control circuit 201 does not advance the start time of the transparent signal ON for the display unit 7 relative to the switching signal, or does not turn the scattering signal ON for the display unit 8 immediately before the switching signal. By controlling the timing so as to provide an OFF period, color deterioration can be reduced. FIG. 8 also shows an example in which the display unit 8 is colored white and the display unit 7 is colored red.

When the OFF period shown in FIG. 8 is lengthened, the scattered signal ON period is shortened and the illuminated display portion becomes dark. The OFF period is preferably about 2 ms so as to make the period of the scattering signal ON as long as possible while preventing color mixing caused by maintaining the light scattering state other than the desired light source color.

In addition, as shown in FIG. 9, the timing control circuit 201 controls the timing so that an OFF time is provided between the ON time of each light source 31, 32, 33 and the next ON time, thereby reducing the color deterioration. Can be made. In the example shown in FIG. 9, unlike the example shown in FIG. 8, the scattered signal ON period is not shortened. In the example shown in FIG. 9, the display unit 8 is visually recognized so as to generate RB color mixture, and the display unit 7 is visually recognized so as to generate GB color mixture.

Further, as shown in FIG. 10, the timing control circuit 201 performs timing control so as to provide an OFF time between the ON time of each light source 31, 32, 33 and the next ON time, and each light source 31, 32. , 33 can be also controlled by timing control so that the scattering signal ON and the transparent signal ON are started before turning OFF. In the example shown in FIG. 10, the display unit 8 is visually recognized so as to generate RB mixed color, and the display unit 7 is visually recognized so as to generate GB mixed color.

By using the field sequential color system, it is possible to simultaneously obtain a desired color in each area of the display element 1. For example, the sign 8 (see FIG. 5) can be displayed in green, the sign 7 (see FIG. 5) can be displayed in red, and the sign 9 (see FIG. 5) can be displayed in blue. It is also possible to change the color according to the display content, and it is easy to grasp the user's information by changing the color. In addition, from the transparent portion, the observed indication in the background can be seen without any problem.

Further, when the three light sources 31, 32, and 33 are provided and the display unit is in a light scattering state, red, RG mixed color, RB mixed color, RGB mixed color (white), green, It is possible to develop a color mixture of GB and seven colors of blue. In other words, when the light source is not turned on and the transparency when the display unit is in a light transmitting state is included, eight colors can be developed. Furthermore, if black is included due to external light when the light source is not turned on and the display portion is in a light scattering state, nine colors can be developed. When the mixed color is referred to as multi-color, it is possible to simultaneously perform monochromatic display and multi-color display on different display portions in one display element 1.

Also, in one display unit, the display color may be a single color and the display color may be a multicolor at different timings. For example, the display unit 7 emits red light in a certain period and RB mixed color is developed in another period. If the display color is a single color and the display color is multicolor at different timings, for example, the indicator 7 indicating the remaining battery level may be displayed in a different color depending on the remaining battery level. When the camera is in focus, the sign indicating the focus area can be displayed in green, and when the focus is not in focus, it can be displayed in red.

Further, in each of the examples shown in FIGS. 6 and 8 to 10, the timing control circuit 201 basically has one type of the length of the scattered signal ON period, but the length of the period of the scattered signal ON. By variably controlling, more types of color development can be achieved.

In the present embodiment, the case where the three light sources 31, 32, and 33 are provided as the light source 2 is exemplified. However, two light sources that emit different light source colors may be used. Even when two light sources are used, a multi-color display color corresponding to the light source color can be obtained in the display element 1 by the field sequential color method.

Further, in the examples shown in FIGS. 4, 6, and 8 to 10, three light sources 31, 32, and 33 are provided as the light source 2. However, as shown in FIG. One light source 22 that emits light (in the example shown in FIG. 11A, one on the left and one on the right) may be provided.

In the configuration in which one light source 22 is provided as shown in FIG. 11A, when the signs 7 and 8 are displayed so as to be visible as shown in FIG. 11B, for example, light from the light source 22 is displayed. In synchronization with the emission, the electrode connected to the marker 7 is driven to change the state of the region of the marker 7 to the light scattering state, and the marker 7 is colored with the light source color. Further, as shown in FIG. 11C, the electrode connected to the marker 8 is driven to change the state of the region of the marker 8 to a light scattering state. At this time, the light source 22 is not controlled to be in a lighting state, but the light transmittance is reduced by the portion corresponding to the sign 8 being in a light scattering state, and the area of the sign 8 is transparent to the viewer. The region (region other than the region of the sign 8) is visually recognized as a dark portion, that is, substantially black when viewed through the eyepiece 314. Even when one light source 22 is used, the frame frequency of the light source 22 is preferably 15 Hz or more, and more preferably 30 Hz or more, in order to prevent flicker from being visually recognized. More preferably, it is 60 Hz or more.

The ratio of the light emission period in one frame is preferably 1/3 or less. When the light emission period exceeds 1/3, there is no problem with red display, but black becomes thin and it is difficult to visually recognize black. Furthermore, it is more preferable if the ratio of the light emission period is 1/6 or less. If it is longer than 1/6, there is almost no problem with black display, but depending on the irradiation intensity of the light source, there is a possibility that the red display becomes light and it is difficult to visually recognize red due to insufficient irradiation time.

Further, when a sign indicating the focus area as shown in FIG. 21 is displayed, a light source 22 that emits red is used, and the scattering signal is periodically turned on. The light source 22 may not be turned on when the focus is not achieved, and may be turned on in synchronization with the scattered signal when the focus is achieved. In that case, when it is out of focus, it is visually recognized as a dark part like the area of the sign 8, and when it is in focus, it is visually recognized as red. That is, the visibility as to whether or not the focus is achieved is further improved.

Further, the image display device 10 according to the present invention is not limited to a camera finder device, but is used for an observer to observe an object to be observed through a transparent window, such as an optical microscope and binoculars. The present invention can be widely applied to a purpose of superimposing information display through a fluoroscopic window or the like.

FIG. 12 is an explanatory diagram for explaining the operation of the light guide unit 4. The light emitted from the light source 2 is repeatedly reflected on the surface within the light guide 4 and spreads over a wide range (after spreading from one end of the side of the display element 1 to the other end). ) Is incident on the liquid crystal layer of the display element 1, but all of the R light sources 31a and 31b, the G light sources 32a and 32b, and the B light sources 33a and 33b in the light source 2 are as shown in FIG. When light is incident on the side surface of the liquid crystal layer of the display element 1 from the light guide portion 4, it is incident on all sides from one end of the liquid crystal layer side surface to the other end (from the upper end to the lower end in FIG. 12A). It is preferable to do. In the present embodiment, the light sources 2 are provided on both sides of the display element 1, but the light sources 2 may be provided only on one side.

Therefore, as shown in FIG. 12B, a lens 11 is provided between the light source 2 and the light guide unit 4 to widen the irradiation range of light from the R light source 31a, the G light source 32a, and the B light source 33a. May be installed. FIG. 12B shows only the left light sources 31a, 32a, and 33a in FIG. 12A, but the same applies to the right light sources 31b, 32b, and 33b. 12B shows an example in which one lens is provided, but the lens may be provided corresponding to each of the light sources 31a, 32a, and 33a.

Further, as shown in FIGS. 12C and 12D, the light emitted from the light source 2 exits outside the light guide 4 (upper and lower in FIGS. 12C and 12D). However, it is preferably incident on the liquid crystal layer of the display element 1. Note that FIG. 12D is a view when the light guide 4 is viewed from the display element 1, and the solid circle in FIG. 12D indicates the traveling direction of light from the light sources 31a, 32a, and 33a. Is shown. 12C and 12D show only the left light source 2 ( light sources 31a, 32a, and 33a) in FIG. 12A, but the right light sources 31b, 32b, and 33b are also shown. It is the same.

Although surface reflection is repeated in the light guide unit 4, when a reflective element is attached to the front or back surface of the light guide unit 4, scattering occurs and light reaches the display element 1. It is conceivable that light leaks to the outside of the light guide unit 4 before. Therefore, as shown in FIGS. 12E and 12F, an optical fiber 41 may be used as the light guide unit 4. That is, if glass or synthetic resin is used for the core (core) and the clad (outer peripheral part) and the refractive index of the core is made higher than the refractive index of the clad, the light incident from the light source 2 is caused by total reflection or refraction. The light propagates only through the core of the optical fiber 41 and enters the side surface of the liquid crystal layer of the display element 1 without leaking outside. FIG. 12F is a view when the light guide 4 is viewed from the display element 1 side. FIGS. 12E and 12F show only the left light source 2 ( light sources 31a, 32a, and 33a) in FIG. 12A, but the right light sources 31b, 32b, and 33b are also shown. It is the same. Further, since the thickness of the optical fiber 41 is as thin as approximately the same thickness as the liquid crystal layer of the display element 1, the light emitted from the optical fiber 41 is displayed substantially parallel to the surface of the display element 1. It can be said that the light enters the element 1.

Examples of the present invention are shown below. In the examples, “%” means mass%.

Example 1
Nematic liquid crystal having negative dielectric anisotropy (Tc = 98 ° C., Δε = −5.6, Δn = 0.220) 85% and bifunctional curable compound 12.5 shown in FIG. %, 2.5% of the bifunctional curable compound shown in FIG. 3E, and benzoin isopropyl ether as a photopolymerization initiator were mixed. About benzoin isopropyl ether, when the sum total of the sclerosing | hardenable compound (The compound shown to FIG. 3 (A) and the compound shown to FIG. 3 (E)) was made into 100%, it mixed so that it might become 1%. And in order to make a liquid mixture phase into a liquid crystal phase, it heated at 90 degreeC, stirring, after making it into an isotropic phase and making a liquid mixture uniform, temperature was lowered | hung to 60 degreeC. Thereafter, it was confirmed that the mixed layer became a liquid crystal phase.

A liquid crystal cell was produced as follows. A small amount of resin beads (diameter: 6 μm) dispersed on a pair of substrates 101, 108 on which vertical alignment polyimide thin films 103, 106 are formed on transparent electrodes 102, 107 so that the vertical alignment polyimide thin films 103, 106 face each other. The liquid crystal cell was formed by bonding together with an epoxy resin (seal layer) printed on the four sides with a width of about 1 mm. Next, the above mixed solution was poured into the liquid crystal cell.

With the liquid crystal cell held at 33 ° C., UV light of 10 mW / cm ² from the upper side and about 10 mW / cm ² from the lower side is irradiated for 10 minutes with an HgXe lamp having a dominant wavelength of about 365 nm to obtain a liquid crystal / polymer composite A display element in which a liquid crystal layer composed of the above was formed between the substrates was obtained.

The display element thus obtained exhibited a uniform transparent state when no voltage was applied. When a voltage of a rectangular wave of 200 Hz and 60 V was applied to the display element, the display element changed to cloudiness. When the transmittance was measured with a schlieren optical system (F-number of the optical system: 11.5, condensing angle: 5 °) using a measurement light source having a half-width of about 20 nm with a center wavelength of 530 nm, the transmittance was 80 with no voltage applied. The contrast value obtained by dividing this value by the transmittance when 60 Vrms was applied was 18.

As the light source 2, a red (R) LED light source was used. The relationship shown in FIG. 14 was used as the relationship between the light source and the drive signal of the display element. The display units 7, 8, and 9 correspond to the indicator 7 indicating the remaining battery level, the indicator 8 indicating the shootable range, and the indicator 9 indicating the shutter speed, respectively, in FIG. In FIG. 14, in a display mode (light emission frame) with time-division driving for red display and black display, the light source is turned on in correspondence with the portion to be displayed in red, that is, the display on the display unit 7 in this embodiment. In the display mode (non-light emitting frame) in which the time division driving for red display and black display is not performed, the light source is completely turned off. The frame frequency was 60 Hz and the OFF period was 2 ms. In the present embodiment, in the portion where red display is desired, that is, in the display unit 7 here, the light source ON is delayed from the time during which the scattered signal is turned on, that is, the OFF time is provided before the light source lighting period.

Then, the display element 1 is arranged as a display element of the image display apparatus 10 installed inside the camera finder apparatus as shown in FIG. 4, and the indicator 7 indicating the remaining battery level, the imageable range as shown in FIG. The indicator 8 indicating the shutter speed and the indicator 9 indicating the shutter speed can be displayed on the display element 1, respectively. In the light emission frame, the marker 7 was visually recognized as red, the marker 8 was black, and the marker 9 was blacker than the marker 8. In the non-light-emitting frame, the sign 7 is not visually recognized, the sign 8 is visually recognized as black, and the sign 9 is visually recognized as blacker than the sign 8, and the flare of the entire element due to the LED light source is not visually recognized on the display element.

(Example 2)
In the same manner as in Example 1, a display element in which a liquid crystal layer composed of a liquid crystal / polymer composite was formed between substrates was produced.

As the light source 2, only one type of LED light source of red (R) was used. The relationship shown in FIG. 15 was used as the relationship between the light source and the drive signal of the display element. The display units 7, 8, and 9 have the same meaning as in the first embodiment. In this embodiment, in the same manner as in the first embodiment, the light source is turned on and off in accordance with the light emitting frame and the light non-emitting frame, and in the display mode in which there is no time division driving for red display and black display, time division is performed. Switching from driving to non-time-division driving was performed, or time-division driving was performed with the ratio to black being 100%. That is, in this case, in the light non-emission frame, the time during which the scattering signal is OFF during the light source lighting period by the time-division driving is also set to the scattering signal ON to prevent the effective voltage from being lowered. It is characterized in that a more preferable dark black display is performed than a preferable black display in time-division driving. The frame frequency was 60 Hz and the OFF period was 2 ms. In the present embodiment, in the portion where red display is desired, that is, in the display unit 7 here, the light source ON is delayed from the time during which the scattered signal is turned on, that is, the OFF time is provided before the light source lighting period.

Then, the display element 1 is arranged as a display element of the image display apparatus 10 installed inside the camera finder apparatus as shown in FIG. 4, and the indicator 7 indicating the remaining battery level, the imageable range as shown in FIG. The indicator 8 indicating the shutter speed and the indicator 9 indicating the shutter speed can be displayed on the display element 1, respectively. In the light emission frame, the marker 7 was visually recognized as red, the marker 8 was black, and the marker 9 was blacker than the marker 8. In the non-light-emitting frame, the marker 7 is not visually recognized, the marker 8 is darker than the first embodiment, and the marker 9 is visually recognized as lighter than the marker 8, and the display element visually recognizes the flare of the entire element by the LED light source. It never happened.

(Example 3)
In the same manner as in Example 1, a display element in which a liquid crystal layer composed of a liquid crystal / polymer composite was formed between substrates was produced.

As the light source 2, only one type of LED light source of red (R) was used. The relationship shown in FIG. 16 was used as the relationship between the light source and the drive signal of the display element. The display units 7, 8, and 9 have the same meaning as in the first embodiment. In this embodiment, in the same manner as in the first embodiment, the light source is turned on and off in accordance with the light emitting frame and the light non-emitting frame, and in the display mode in which there is no time division driving for red display and black display, time division is performed. Switching from driving to non-time-division driving was performed, or time-division driving was performed with the ratio to black being 0%. That is, in this case, in the non-light-emitting frame, the scattering signal to all the display units is turned off. The frame frequency was 60 Hz and the OFF period was 2 ms. In the present embodiment, in the portion where red display is desired, that is, in the display unit 7 here, the light source ON is delayed from the time during which the scattered signal is turned on, that is, the OFF time is provided before the light source lighting period.

Then, the display element 1 is arranged as a display element of the image display apparatus 10 installed inside the camera finder apparatus as shown in FIG. 4, and the indicator 7 indicating the remaining battery level, the imageable range as shown in FIG. The indicator 8 indicating the shutter speed and the indicator 9 indicating the shutter speed can be displayed on the display element 1, respectively. In the light emission frame, the marker 7 was visually recognized as red and the marker 8 was viewed as black, and the marker 9 was not visually recognized. In the non-light emitting frame, none of the signs 7, 8, and 9 was visually recognized, and the flare of the entire element by the LED light source was not visually recognized on the display element.

Example 4
In the same manner as in Example 1, a display element in which a liquid crystal layer composed of a liquid crystal / polymer composite was formed between substrates was produced.

As the light source 2, only one type of LED light source of red (R) was used. The relationship shown in FIG. 17 was used as the relationship between the light source and the drive signal of the display element. The display units 7, 8, and 9 have the same meaning as in the first embodiment. In the present embodiment, as in the first embodiment, the light source is turned on and off according to the light emitting frame and the light non-emitting frame, and in the display mode in which there is time-division driving for red display and black display, In a display mode in which the scattering signal is turned off in all the display units at a time corresponding to black of the emission frame and there is no time-division driving for red display and black display, the scattered signals to all the display units are sent as in the third embodiment. OFF. That is, the time division drive in the present embodiment corresponds to a display mode of red display and time division of the transparent state. The frame frequency was 60 Hz and the OFF period was 2 ms. In the present embodiment, in the portion where red display is desired, that is, in the display unit 7 here, the light source ON is delayed from the time during which the scattered signal is turned on, that is, the OFF time is provided before the light source lighting period.

Then, the display element 1 is arranged as a display element of the image display apparatus 10 installed inside the camera finder apparatus as shown in FIG. 4, and the indicator 7 indicating the remaining battery level, the imageable range as shown in FIG. The indicator 8 indicating the shutter speed and the indicator 9 indicating the shutter speed can be displayed on the display element 1, respectively. In the light emission frame, the sign 7 was visually recognized as red, and the signs 8 and 9 were not visually recognized. In the non-light emitting frame, none of the signs 7, 8, and 9 was visually recognized, and the flare of the entire element by the LED light source was not visually recognized on the display element.

(Example 5)
In the same manner as in Example 1, a display element in which a liquid crystal layer composed of a liquid crystal / polymer composite was formed between substrates was produced.

As the light source 2, only one type of LED light source of red (R) was used. The relationship shown in FIG. 18 was used as the relationship between the light source and the drive signal of the display element. The display units 7, 8, and 9 have the same meaning as in the first embodiment. In the present embodiment, compared with the first embodiment, the portion for which red display is desired, that is, the time during which the display portion 7 that is desired to be displayed in red is turned on from scattering is switched from the timing at which the black display is changed from scattering to transparent. Slightly earlier and delay the light source ON from the time when the scattered signal is turned on, and when the light source is turned off, the timing for switching the scattered signal of the display unit 7 to be displayed in red to the transparent signal is slightly delayed from the timing when the light source is turned off.

This makes it possible to avoid the occurrence of a situation in which the light scattering state is maintained even if the light source color is other than the desired light source color.

Note that this embodiment is particularly effective when the rising speed of the liquid crystal is slow, such as when the display element is driven at a low temperature or when the driving voltage of the liquid crystal is low.

(Comparative Example 1)
In the same manner as in Example 1, a display element in which a liquid crystal layer composed of a liquid crystal / polymer composite was formed between substrates was produced.

As the light source 2, only one type of LED light source of red (R) was used. The relationship shown in FIG. 19 was used as the relationship between the light source and the drive signal of the display element. The display units 7, 8, and 9 correspond to the indicator 7 indicating the remaining battery level, the indicator 8 indicating the shootable range, and the indicator 9 indicating the shutter speed, respectively, in FIG. The frame frequency was 60 Hz and the OFF period was 1 ms.

Then, the display element 1 is arranged as a display element of the image display apparatus 10 installed inside the camera finder apparatus as shown in FIG. 4, and the indicator 7 indicating the remaining battery level, the imageable range as shown in FIG. The indicator 8 indicating the shutter speed and the indicator 9 indicating the shutter speed can be displayed on the display element 1, respectively. When the image display device 10 was visually confirmed, the sign 7 was visually recognized as red, the sign 8 was black, and the sign 9 was darker than the sign 8 in the light emission frame. In the non-light-emitting frame, the marker 7 was not visually recognized, but the marker 8 was visually recognized as black and the marker 9 was viewed as blacker than the marker 8. The black of the sign 8 was not clearly displayed as compared with the black display of the sign 8 of Example 2. Moreover, the flare of the whole element by the LED light source was visually recognized by the display element in the non-light emission flame | frame which does not display red on a label | marker.

The present invention has been described above with reference to the embodiments and examples, but the present invention is not limited to the above embodiments and examples. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

This application is based on a Japanese patent application (Japanese Patent Application No. 2009-132733) filed on June 2, 2009, the contents of which are incorporated herein by reference.

The present invention can be particularly preferably applied to a screen display device that does not require the light source to always emit light, for example, the light source is colored in conjunction with a camera operation button.

DESCRIPTION OF SYMBOLS 1 Display element 2 Light source 3 Observer 4 Light guide part 7, 8, 9 Sign (display part)
DESCRIPTION OF SYMBOLS 10 Image display apparatus 20 Drive circuit 22 Light source 41 Optical fiber 101,108 Glass substrate 102,107 Transparent electrode 103,106 Alignment film 104 Liquid crystal layer 105 Seal layer 201 Timing control circuit 202 Voltage generation circuit 203 Electrode drive circuit 204 Electrode drive circuit 205 Temperature sensor 300 Camera body 311 Mirror 312 Liquid crystal display panel 313 Prism 314 Eyepiece 315 Viewing window 316 Drive circuit 320 Lens cylinder 321 Lens

Claims (11)

1. A transparent substrate with a pair of electrodes and a liquid crystal layer that is sandwiched between the pair of substrates with a pair of electrodes and can take a light transmission state and a light scattering state. A display element in a scattering state;
   A light source that causes light substantially parallel to the surface of the liquid crystal layer to enter the liquid crystal layer;
   A timing control circuit for causing at least a part of the display surface of the display element to be in a light scattering state or a light transmission state in conjunction with a state of light emission to the liquid crystal layer in the light source in the presence of external light. ,
   The light source has a non-light-emitting frame and the light source has a light-emitting frame. In the non-light-emitting frame, at least part of the display surface of the display element is in a light-scattering state so that external light is emitted. In accordance with the light emission frame, in the light emission frame, the display color corresponding to the light source color is obtained by causing at least a part of the surface of the display element to be in a light scattering state in synchronization with the color development of the light source. The timing control circuit causes at least a part of the display surface of the display element to be in a light scattering state in conjunction with at least a part of a predetermined light non-emission period provided in the light emission frame. An image display device having a function of transmitting light from an observation object.
2. The image according to claim 1, wherein in the frame where the light source is not emitting light, at least a part of the display surface of the display element is caused to be in a light-scattering state in all periods within the frame to obtain a display color corresponding to external light. Display device.
3. The light source develops one light source color,
   The image display device according to claim 1, wherein the frame frequency is 15 Hz or more.
4. The image display device according to claim 3, wherein the light source color is red.
5. The light source emits one light source color,
   The frame frequency is 15Hz or more,
   The image display device according to claim 3 or 4, wherein a ratio of a light emission period in one frame is 1/3 or less.
6. The light source sequentially emits two or more light source colors,
   The frame frequency is 15Hz or more,
   The image display device according to claim 1, wherein a ratio of a light emission period in one frame is 1/3 or less.
7. The image display device according to claim 6, wherein the light source is capable of coloring red, blue, and green independently.
8. The light guide part which spreads the light radiate | emitted from the said light source from one edge part in the side part of a liquid-crystal layer to the other edge part between the said light source and the display apparatus was provided. The image display device according to any one of the above.
9. A camera finder device including the image display device according to any one of claims 1 to 8.
10. An optical microscope including the image display device according to any one of claims 1 to 8.
11. Binoculars including the image display device according to any one of claims 1 to 8.

Images