JPH0331833A - Variable stroboscopic diffusion plate device - Google Patents

Abstract

PURPOSE:To carry out a proper stroboscopic irradiation suitable for each object in an image plane by using a stroboscopic diffusion plate wherein a high molecular layer obtained by dispersing liquid crystals having positive dielectric anisotropy into specific transparent high molecules is provided between transparent electrodes. CONSTITUTION:The stroboscopic diffusion plate 10 is composed of transparent substrates 11 and 17, the transparent electrodes 12 and 16, and a high molecular material layer 15, wherein the liquid crystals consisting of nematic liquid crystals 13 having the positive dielectric anisotropy and high molecular materials 14 are dispersed, between the electrodes 12 and 16. This diffusion plate 10 is driven by a control part/ power source part 18. In the diffusing plate 10 having this constitution, when a voltage is not applied to the layer 15, the liquid crystals in the layer 15 are orientated at random, therefore light beams are diffused and a light quantity can be secured in all photographing areas even when photographing is performed by using a wide angle lens. A diffused light quantity goes down as the voltage is applied, and comes to concentrate on a central part, so that the diffusion plate can cope with various types of photographing lenses.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention relates to a strobe diffuser device using liquid crystal, and particularly to a variable strobe diffuser device whose diffusion characteristics can be controlled.

(Background of the Invention) Conventionally, strobe devices have been used in photography as a means to compensate for insufficient light. The strobe device is
It irradiates in a fixed angle direction, but if the light source has the same amount of light, if the light is irradiated at a wide angle, the reach of the light will be reduced and the effectiveness of light utilization will be reduced. The light irradiation angle of the strobe device is set to an angle equal to or higher than that of a frequently used 35 mm lens. For wider angle lenses, a removable light diffusing plate is used. As the removable light diffusing plate, a transparent substrate equipped with a Fresnel lens or a uniform white plate is used. These strobe light diffusers are used to reduce the intensity of light reaching the subject in order to diffuse the light, prevent excessive light intensity, and provide appropriate exposure when the subject is close to the subject. In some cases.

In addition, an inner zoom type strobe device is also used in which the light irradiation angle is changed by moving the light source. FIG. 10 schematically shows this type of conventional inner zoom type strobe device. In the figure, 101 is a light source with a reflecting mirror, and 102 is a reflecting member that forms an optical path.

This is because when the light source 101 is at the position indicated by the solid line, the irradiation angle of the strobe light is narrowed by the reflecting member 102. Therefore, it is suitable for photographing with a telephoto lens. Further, as the light source 101 is moved from the solid line position to the dotted line position, the irradiation angle of light is expanded, and it becomes possible to correspond to a wide-angle lens.

In addition, although it was not devised as a variable strobe diffuser, nematic liquid crystals are dispersed in a polymer material film, and the direction of the liquid crystal molecules is controlled by voltage, and the birefringence of the liquid crystal and the refractive index of the polymer material are controlled. A liquid crystal element that controls light diffusion based on the difference in light is disclosed in Japanese Patent Publication No. 58-501631.

This liquid crystal element is formed of a member in which the ordinary ray refractive index n0 of the liquid crystal and the refractive index of the polymer substance are approximately equal. When no voltage is applied, the liquid crystals dispersed in the polymer material are oriented in a certain direction for each domain. Also, at this time,
The orientation of the liquid crystal indicated by each domain exists randomly in the polymeric material film. As a result, when no voltage is applied,
This element forms a diffused state based on the difference between the extraordinary ray refractive index ne of the liquid crystal and the refractive index of the polymer material. When a voltage is applied to this liquid crystal element, a force acts on the liquid crystal molecules in each domain in the polymer film to orient them in the direction of the electric field. A certain equilibrium state is reached by this force, the alignment regulating force received from the polymer film, and the elastic energy of the liquid crystal. When the liquid crystal molecules follow the direction of the electric field, the device forms a good transmission state. Furthermore, at intermediate voltages, the diffusion state also becomes intermediate.

However, the above conventional example had the following problems.

First, regarding the removable light diffusion plate, since it is attached and used when changing lenses, it takes time to attach and detach, and there is a problem that you may miss a photo opportunity, especially when taking pictures. . Furthermore, it is cumbersome because several types of light diffusing plates must be prepared and a desired one must be selected and used depending on the photographic lens and photographing conditions.

In addition, when using it for the purpose of suppressing the intensity of light, such as when you want to capture both the nearby main subject and the distant background, simply using a diffuser plate like this will reduce the amount of light reaching the background. However, there was a problem in that the result was a photograph that did not suit the purpose.

Next, regarding inner zoom type strobe devices,
Since the light source 101 (or the reflecting member 102) must be driven, there is a problem in that the device becomes large. Furthermore, although this method allows the light diffusion angle to be changed, it is not possible to form a light irradiation pattern with an intensity distribution tailored to the subject, as in the case of a removable light diffusion plate.

Next, regarding the device disclosed in Japanese Patent Publication No. 58-501631, a liquid crystal element formed by dispersing nematic liquid crystal in a polymeric material film has a function as a diffuser plate. When the element was used as a variable strobe diffuser for a camera, it was not possible to arbitrarily form the distribution of light intensity.

(Objective of the Invention) The first object of the present invention is to achieve a variable device that can miniaturize the device and instantaneously perform strobe irradiation suitable for each subject within the screen without any troublesome operations. An object of the present invention is to provide a strobe diffuser plate device.

A second object of the present invention is to provide a variable strobe diffuser device that can extend the life of the strobe diffuser.

(Features of the Invention) In order to achieve the above object, the present invention provides a transparent electrode having a plurality of regions disposed on one opposing surface of a pair of transparent substrates, a transparent electrode disposed on the other surface of the transparent substrate. A transparent electrode having at least one region, and a liquid crystal having a positive dielectric anisotropy between the transparent electrodes, a transparent polymer material having no dielectric anisotropy and having a refractive index substantially equal to the ordinary refractive index of the liquid crystal. A strobe diffuser plate formed by a polymer material layer dispersed therein, and a drive control means for independently driving each of the plurality of regions, and the drive control means is selected according to the shooting situation. It is characterized by controlling the drive of each area and changing the state of diffusion of strobe light within the screen.

Further, an ultraviolet absorbing member is provided, which is formed on either the light source side or the subject side of the polymeric material layer, or is formed on both the light source side and the subject side of the polymeric material layer. It is characterized by reducing the incidence of ultraviolet rays into the polymer material layer.

(Embodiment of the invention) FIGS. 1 to 4 are diagrams showing a first embodiment of the invention.

FIG. 1 is a schematic cross-sectional view of a strobe diffuser plate, and in this figure, 10 is a strobe diffuser plate, and 11 to 1, which will be described later.
It is composed of each part shown by 7. 11 and 17 are transparent substrates, and 12 and 16 are also transparent electrodes, of which the transparent electrode 12 is formed with an electrode pattern having a structure to be described later. 13 is a nematic liquid crystal with positive dielectric anisotropy, 1
4 is a polymer material in which the liquid crystal 13 is dispersed; 15 is a polymer material layer composed of the liquid crystal 13 and the polymer material 14; 18 is a layer of polymer material in which the liquid crystal is dispersed; The control section and power supply section are isolated.

FIG. 2 is a diagram showing a pattern of transparent electrodes formed on the transparent substrate 12 of FIG. 1 and a specific configuration of the control section/power supply section 18, in which 21 is an electrode section and 22 is a Non-electrode portion, 23 is the effective area of the variable strobe diffuser, 2
Reference numeral 4 represents an electrode lead-out portion, and 25 represents a lead-out line. 26 is a drive control section, which together with the power supply section 27 is connected to the control section/power supply section 1.
8. 28 is a lead line to the opposing transparent electrode 16.

FIG. 3 is a diagram illustrating a method of driving the variable strobe diffuser masquerade constructed as described above. As can be seen from the figure, there are nine areas from ① to . Further, 32 is a photographing area, 33 is an adjacent main wave fJ body, and 34 is a background.

FIG. 4 is a side view showing the case where the variable strobe diffuser device of the first embodiment is used as a light diffuser for a single-lens reflex L/TSX camera, and in this figure, numeral 41 indicates the variable strobe diffuser device; 42 is a strobe body that integrally has the above-mentioned device 41, 4:3 is a camera body, and 44 is a lens.

In this embodiment, the polymer substance 15 containing liquid crystal dispersedly contains a nematic liquid crystal 13 having positive dielectric anisotropy.
It is dispersed and contained in a polymer having a refractive index substantially equal to the ordinary ray refractive index n6 of n6.

In this example, the refractive indexes being substantially equal to 2 means that the refractive index difference is within 0.05 with a difference of 5 refractive indexes.

Next, the variable strobe diffuser device 4 in the first embodiment
Before proceeding to the explanation of the operation of step 1, the explanation of the configuration of the rainbow device 41 will be slightly supplemented.

The transparent electrode 16 in FIG. 1 is a −-like ↑ plane electrode (common electrode), and the transparent electrode 12 is an electrode divided into nine regions @ to ■, as described above, and each region can be separated independently. Electrical connections are made so that it can be driven. To explain in more detail, a control dial (not shown) is provided in each region (■ to ■ is controlled by an arbitrary applied voltage),
The photographer controls the diffusion characteristics of the intended area using the control dial as necessary. Note that this can also be implemented by selecting any pre-registered state using a microcomputer. In addition, in Fig. 2, the central area (area ■~ shown in Fig. 3)
In order to suppress the influence of the voltage drop of the transparent electrode 12 itself, the extraction electrode portions 2 (a) are provided at two or more locations, and an extraction line 25 is provided at each location.

Next, the variable strobe diffuser device 4 in the first embodiment
The first operation will be described.

When no voltage is applied to the polymer material 115 containing dispersed liquid crystals, the liquid crystals in the polymer material 115 are randomly oriented, so light is diffused, making it difficult to take pictures using a wide-angle lens. However, the amount of light can be ensured in the entire shooting area. Further, as voltage is applied, the amount of diffused light decreases and the amount of light is concentrated in the center, making it compatible with various photographic lenses.

In addition, if the subject is close to each other, by selecting only the part in that direction to apply a non-voltage, you can prevent overexposure of the nearby subject and provide sufficient light for the background. It becomes possible to irradiate. Here, this will be explained in detail using FIG.

In the photographing area 32, there is a main subject 33 that is close to the subject and a background 34 that is slightly distant. At this time, in conventional strobe photography, the main subject 33 would be overexposed, and
If the entire image is taken in a diffused state, light of sufficient intensity will not reach the background 34, and the background 34 will not be captured clearly.

However, in the first embodiment of the present invention, ■ and ■.

The main subject 33 and the background 3 are set to a diffused state by using the aforementioned control dial (not shown) in the three regions (2), and the other regions are set to a transparent state by applying a voltage.
4, it is possible to make clear impressions. Furthermore, since the applied voltage can be varied as necessary, when the strobe body 42 in FIG. 4 is in a zooming state compatible with a lens system with a large shooting angle,
When a low voltage is applied to a zooming state that corresponds to a telephoto lens system with a small photographing angle, by applying a high voltage, it is possible to perform photographing using the amount of light effectively.

Next, an example of a method for manufacturing the strobe diffuser plate 10 used in the above embodiment will be described.

Polyvinyl alcohol (PVA) having a degree of polymerization of about 500 is dissolved in water and sufficiently purified by reprecipitation using methanol to prepare a 10% PVA aqueous solution. This solution Log
2 g of Z L 12914 (registered trademark) from Merck & Co. was mixed with the mixture and stirred to form an emulsion. After being left at room temperature for about 1 hour, it is dropped onto a glass substrate equipped with a transparent electrode as shown in FIG. 1, and stretched to form a film with a thickness of about 10 am. Furthermore, after drying this film at room temperature for 5 hours, a counter substrate is pressed against it to produce the device.

In addition, the strobe diffuser plate 10 produced in the above example
It is possible to obtain the same effect by attaching a removable variable strobe diffuser plate device to the entire surface of the light irradiation part of the strobe device.

FIGS. 5 to 7 are diagrams showing a second embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view of the strobe diffuser plate in the second embodiment, and in this figure, 50 is the strobe diffuser plate, which is composed of parts 51 to 57, 59A, and 59B, which will be described later. .

51 and 57 are transparent substrates, and 52 and 56 are also transparent electrodes, of which the transparent electrode 52 is formed with an electrode pattern having a structure described later. 53 is a nematic liquid crystal with positive dielectric anisotropy, 54 is a polymeric material containing this liquid crystal 53 dispersed therein, and 55 is the liquid.

A polymer material layer containing liquid crystal dispersed therein is composed of a crystal 53 and a polymer material 54, 58 is a control section/power supply section for driving the strobe diffuser plate 50, and 59A59B is an ultraviolet absorbing member (or ultraviolet reflecting member). It is.

FIG. 6 shows a pattern of the transparent electrode 52 formed on the transparent substrate 51 of FIG.
62 is an electrode portion, 62 is a non-electrode portion, 63 is an effective area of the variable strobe diffuser device, and 64 is an electrode extension portion. Also,
■ and ■ indicate two divided areas.

FIG. 7 shows a case where the variable strobe diffuser device according to the second embodiment of the present invention is used as a light diffuser for a zoom lens shutter camera, and in this figure, 71 is the variable strobe diffuser device according to the second embodiment of the present invention. In the example variable strobe diffuser device, 72 is a viewfinder, 73 is a shutter button, 74 is a grip, 75
is a zoom lens, and 76 is an AF distance measuring unit.

Next, the driving method will be explained.

In a zoom type lens shutter camera equipped with a 28-80 mm lens, the effective range that can be covered by the strobe light when the strobe diffuser plate 50 is in a transmitting state is set to the telephoto side of the 50 mm lens.

In this camera, when shooting at a wider angle than 50 mm, by reading the lens data, voltage application to the strobe diffuser plate 50 is stopped even when the light is being emitted.
Light is diffused. In addition, when shooting at the telephoto side of 50 mm or more, the first stroke of the shutter button
A rectangular wave of 1 KHz and 30 square waves is applied, and the strobe diffuser plate 50 enters a transmitting state. At this time, the light is not diffused and reaches a long distance, allowing a long shooting distance. Further, when there is a subject to be photographed in the vicinity or behind, it is possible to photograph only the area O in a transparent state by using a mode select switch (not shown). This mode suppresses overexposure of close-up images,
At the same time, it is possible to clearly photograph distant backgrounds.

In addition, in the variable strobe diffuser device 71 of the above embodiment, ultraviolet absorbing members 59 are provided on the strobe light emission side and the irradiation side.
A and 59B are provided, it is possible to reduce the amount of ultraviolet light reaching the liquid crystal, prevent deterioration of the liquid crystal, and extend the life of the strobe diffuser plate 50 (the device 71).

Here, some explanation will be added regarding the ultraviolet absorbing (reflecting) member.

The ultraviolet absorbing members 59A and 59B in the above embodiments have a function of reducing the light amount ratio of the ultraviolet component in the transmitted light compared to the incident light when comparing the incident light and the transmitted light when light is transmitted through the members. It shows. Ultraviolet rays generally refer to light in the wavelength range from 380 nm to 1 nm, and it is already known that the ultraviolet rays promote deterioration of liquid crystals.

The ultraviolet absorbing member is a film of a substance that absorbs in the ultraviolet region, or a film containing the same dispersed in a binder, and is supplied in the form of vapor deposition raw materials, sheets, paints, and the like. Furthermore, interference filters and the like are known as ultraviolet reflecting members.

The ultraviolet absorbing member 59 is provided closer to the light source than the liquid crystal.
B has the function of suppressing ultraviolet rays generated by a strobe light source from reaching the liquid crystal. Further, the ultraviolet absorbing member 59A provided closer to the subject than the liquid crystal has the function of suppressing ultraviolet rays contained in external light from reaching the liquid crystal. The above-mentioned ultraviolet rays have unique wavelength components depending on the type of light source, season, location, etc. Further, it is generally considered that ultraviolet rays emitted from a strobe light source have a high intensity but a short irradiation time, and ultraviolet rays contained in external light have a low intensity but a long irradiation time. Therefore, by properly using a plurality of types of ultraviolet reflecting or absorbing members according to the respective types of ultraviolet rays, it is possible to more effectively extend the life of the strobe diffuser plate. Note that it is desirable that the ultraviolet absorbing or reflecting member be as transparent as possible in the visible range so that strobe light can pass through during photographing.

In the embodiment described above, the ultraviolet absorbing members 59A and 59B are formed by forming a titanium oxide film on the surface of the transparent substrate 51, 57 where there is no transparent electrode using a vacuum evaporation method.

According to this embodiment, compared to a strobe device with a detachable diffuser plate, the effort of attaching and detaching the diffuser plate can be saved, and there is an effect that it is difficult to miss a photo opportunity during photographing. Furthermore, since the diffusion state of the strobe light can be changed in accordance with the photographic lens and photographing conditions, there is no need to prepare several types of light diffusion plates and select the desired one for use.

Furthermore, compared to an inner zoom type strobe device, the device can be made smaller because the wave number angle of the light can be controlled without driving the light source or the reflecting member. Furthermore, even when it is desired to capture both a nearby main subject and a distant background, creating a diffused light intensity distribution on the diffuser plate has the effect of instantly adapting to various photographing conditions.

(Modified Example) In this embodiment, the transparent electrode 16.56 serving as the common electrode is a --like electrode, that is, an electrode consisting of one region, but this transparent electrode is divided into multiple regions, and the other transparent electrode A configuration in which the electrode 12.52 is one area may also be used.

In addition, in this embodiment, the transparent electrode 16. which becomes the common electrode.
Although the electrode 56 is made up of one region, the electrode on this side may also be divided into a plurality of regions, and an example of this will be explained with reference to FIGS. 8 and 9.

FIGS. 8 and 9 show the configuration of the first embodiment,
It is formed by dividing both transparent electrodes. In these figures, 8o and 90 are transparent substrates with transparent electrodes having three regions (one of which is on the common electrode side), 81, 82°, 83, 91, 92, and 93 are transparent electrodes, respectively. The electrode part, 84.94 is a transparent electrode extension part, and 85.95 is a non-electrode part. In addition, a control unit (not shown) that can independently and selectively apply a voltage to each transparent electrode via the transparent electrode lead-out portions 84 and 94 is provided.
The power supply is connected.

Next, an example of the driving method will be explained using the above-mentioned Fig. 8.9 and the above-mentioned Fig. 3.

For example, when transparent electrode portions 81.82 and 92.93 are selectively connected and a rectangular wave of IKHz and 30V is applied between both substrates, only the areas marked ■, @■, and ■ in FIG. 3 become transparent. Others maintain a diffused state, and a strobe light intensity distribution state can be formed. Note that if all the transparent electrodes are selected, it is also possible to change the strobe light irradiation state corresponding to each lens by controlling the applied voltage, as in the first embodiment.

With the above configuration, it is possible to select an area of the same size as in the first embodiment while reducing the number of transparent electrode extension parts.

(Effects of the Invention) As explained above, according to the present invention, a transparent electrode having a plurality of regions disposed on one opposing surface of a pair of transparent substrates, a transparent electrode disposed on the other surface of the transparent substrate, A transparent electrode having at least one region, and a liquid crystal having a positive dielectric anisotropy between the transparent electrodes, a transparent polymer material having no dielectric anisotropy and having a refractive index substantially equal to the ordinary refractive index of the liquid crystal. a strobe diffuser formed by a polymeric substance layer dispersed therein; and a drive control means for independently driving each of the plurality of regions, the drive control means being selected according to the shooting situation. By controlling the drive of each area and changing the diffusion state of the strobe light within the screen, the device can be made smaller, and the strobe suitable for each subject within the screen can be achieved without any troublesome operations. Irradiation can be performed instantly.

Further, an ultraviolet absorbing member or an ultraviolet reflecting member is provided which is formed on either the light source side or the object side of the polymer material layer, or is formed on both the light source side and the object side of the polymer material layer. However, since the incidence of ultraviolet rays on the polymer material layer is reduced, the life of the strobe diffuser plate can be extended.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a strobe diffuser plate according to a first embodiment of the present invention, and FIG. 2 is a diagram showing the structure of an electrode pattern formed on the transparent substrate shown in FIG. 1 and its control section and power supply section.
FIG. 3 is a diagram explaining the method of driving the strobe diffuser plate in the first embodiment, FIG. 4 is a side view showing a camera system equipped with the device of the first embodiment, and FIG. FIG. 6 is a cross-sectional view of the strobe diffuser plate in the embodiment shown in FIG. 5, which shows the structure of the electrode pattern formed on the transparent substrate shown in FIG. FIG. 8 and FIG. 9 are diagrams showing other examples of both transparent electrodes in the first embodiment of the present invention, and FIG. 10 explains a conventional strobe device. This is a diagram for 10...Strobe diffuser plate, 11.17...
...Transparent substrate, 12.16 ...Transparent electrode, 15
....polymer material layer, 18 .... control section.
Power supply section, 41... Variable strobe diffuser device, 5
0... Strobe diffuser plate, 51.57...
・Transparent substrate, 52.56...Transparent amount (location, 55
....polymer material layer, 58 .... control section.
Power supply section, 59△, 59B... Ultraviolet absorbing member,
71...Variable strobe diffuser device, 80.90
・・・Transparent substrate, ■～■・・・・・・area. Patent Seller Canon Co., Ltd.

Claims (4)

[Claims] (1) a transparent electrode having a plurality of regions disposed on one opposing surface of a pair of transparent substrates; a transparent electrode having at least one region disposed on the other surface of the transparent substrate;
and a polymer material comprising a liquid crystal with positive dielectric anisotropy dispersed in a transparent polymer having no dielectric anisotropy and having a refractive index substantially equal to the ordinary ray refractive index of the liquid crystal between these transparent electrodes. A variable strobe diffuser device comprising: a strobe diffuser formed by a plurality of layers; and a drive control means for independently driving each of the plurality of regions. (2) The variable strobe diffuser device according to claim 1, further comprising an ultraviolet absorbing member or an ultraviolet reflecting member formed on either the light source side or the subject side of the polymer material layer. (3) The variable strobe diffuser device according to claim 1, further comprising an ultraviolet absorbing member or an ultraviolet reflecting member formed on both the light source side and the subject side of the polymer material layer. (4) The drive control means includes region selection means for independently driving each of the plurality of regions, and voltage variable means for varying the voltage applied to the region selected by the region selection means. The variable strobe diffuser device according to claim 1, 2 or 3, characterized in that: