JPH1096883A - Liquid crystal panel and optical device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate focusing by properly varying a voltage for applying to a transparent electrode divided into plural strips, changing the condition of a liquid crystal layer, and thereby confirming the image of a subject in superb visibility even under such photographing conditions as the subject is bright or the background is glaring. SOLUTION: A liquid crystal panel P is such that a polymer-dispersed liquid crystal, constituted of a mixture with a high polymer substance and liquid crystal dispersed, is sealed in between a pair of transparent glass plates. A transparent common electrode consisting of ITO and the like formed by a vapor deposition method for example is provided inside the two sheets of the transparent glass plates, as are plurally divided segment electrodes 13a, 13a,.... If no voltage is applied between the common electrode and the segment electrode, 13a, 13a, it passes into a transparent state having for example a light transmissivity of 70%; with an AC voltage applied, the direction of the liquid crystal changes only in the area where the common electrode and the segment electrode 13a, 13a are facing with each other, and it turns to a light scattering state, with a contrast of about 15:1 provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal panel, and more particularly to a liquid crystal panel useful for a finder panel of an optical device such as a single-lens reflex camera.

[0002]

2. Description of the Related Art Conventionally, in a camera such as a single-lens reflex camera, when focusing manually, the subject is focused while looking at an image visible in a viewfinder.

[0003] Similarly, it is possible to confirm, for example, whether the photographing is of a standard size or a so-called panoramic size by a mark or the like indicating the photographing range displayed in the viewfinder. As such a finder panel, a panel using a liquid crystal panel has been proposed.

[0004]

However, in the single-lens reflex camera or the like as described above, the finder is used, for example, when the subject is extremely bright, when the background is dazzling like a snow scene, or when the subject is backlit. This makes it difficult to see an image of a subject as an object to be photographed, a mark indicating a photographing range, and the like, making it difficult to focus and make it difficult to confirm the photographing range.

[0005] Therefore, even when the subject is bright, the background is dazzling, or the subject is backlit, the image of the subject as a subject to be photographed in the viewfinder or a mark indicating the photographing range can be confirmed with good visibility. There has been a demand for the development of a technology that can easily perform focusing and confirmation of a shooting range.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image of a subject with good visibility even when the subject is applied to a viewfinder panel such as a camera or the like, even when the subject is bright or the background is dazzling. It is an object of the present invention to provide a liquid crystal panel capable of performing focusing and the like easily and an optical device using the same.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a liquid crystal panel having a liquid crystal layer sandwiched between a pair of transparent substrates. An electrode is provided, the transparent electrode of at least one transparent substrate is divided into a plurality of strips, and the state of the liquid crystal layer can be changed by appropriately changing the voltage applied to each strip-shaped transparent electrode. is there. Therefore,
If this liquid crystal panel is applied to a finder panel of an optical device such as a camera, the voltage applied to each strip-shaped transparent electrode of the liquid crystal panel is adjusted to adjust the light of an image of an object or a background that can be seen through the liquid crystal panel. The degree of scattering can be changed appropriately.For example, when the background is dazzling like a snow scene, the contrast can be increased by adjusting the degree of light scattering of the liquid crystal panel to be strong, and focusing can be performed. It can be easier.

The liquid crystal layer can be composed of a polymer dispersed liquid crystal in which a polymer is dispersed in a liquid crystal layer composed of liquid crystal molecules. In this case, depending on the characteristics of the polymer dispersed liquid crystal, Since it is not necessary to provide a polarizing plate on the transparent substrate, the inside of the finder can be made bright and easy to see.

The plurality of strip-shaped transparent electrodes can be selected alternately or alternately so that a voltage is applied only to the transparent electrodes, or they can be formed at predetermined intervals.

[0010] The plurality of strip-shaped transparent electrodes may be strip-shaped vertical stripes or horizontal stripes, or wavy vertical stripes or horizontal stripes formed to have the same width in the horizontal or vertical direction depending on the application. Alternatively, it can be formed in a concentric shape.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a configuration example of a single-lens reflex camera in which a liquid crystal panel according to the present invention is applied to a finder panel. In FIG. 1, 1 is a camera body case, 2 is a taking lens, 3 is a film, 4 is a reflection mirror, 5 is a pentaprism, 6 is an eyepiece lens, 7 is a finder panel, and 8 is to apply a voltage to a liquid crystal panel LCD. A selection button 9 for selecting an electrode and a contrast adjustment button 9 for changing the amount of change in contrast by increasing or decreasing the voltage applied to the electrode selected by the selection button 8. In the present embodiment, the case where the selection button 8 and the contrast adjustment button 9 are provided on the back cover side of the camera body case 1 has been described. However, the present invention is not limited to this. Can be designed as appropriate.

FIG. 2 is a longitudinal sectional view showing a schematic structure of a liquid crystal panel P applied to the finder panel 7, and FIGS. 3 to 6 are plan views showing an arrangement pattern of segment electrodes of the liquid crystal panel P. . In each of the drawings, parts performing the same functions are denoted by the same reference numerals, and redundant description will be avoided.

As shown in FIG. 2, the liquid crystal panel P
Polymer dispersed liquid crystal (PDLC) 11 composed of a mixture of a polymer substance and a liquid crystal dispersed between a pair of transparent glass plates 10a and 10b.
Is enclosed.

The inner surfaces of the two transparent glass plates 10a and 10b are coated with ITO (Indium-T
, etc., and a plurality of segment electrodes 13, 13,...

Further, an alignment film (not shown) made of polyimide or the like is applied to the surfaces of the electrodes 12 and 13 by spin coating or the like. This alignment film is subjected to an alignment treatment by, for example, rubbing the surface thereof in a predetermined direction. In this case, the orientation directions of the alignment films of the respective substrates are set to be orthogonal to each other, and approximately 1
Transparent glass plates 10a, 10b so that a gap of 0 μm is generated.
Are set by spacers (not shown).

At the periphery of the liquid crystal panel P, a seal member 14 for preventing leakage of the enclosed liquid crystal is provided so as to surround the liquid crystal panel P.

As the polymer-dispersed liquid crystal 11, for example, a mixture of 4-biphenyl methacrylate and liquid crystal PN-001 in a ratio of 1: 9 as a polymer precursor is irradiated with ultraviolet rays to convert the polymer into particles. What is made into a structure dispersed in the above is used.

Thus, when no voltage is applied between the common electrode 12 and the segment electrodes 13, 13,..., A transparent state (reverse mode) with a light transmittance of 70% is obtained. When the voltage is applied, only the portion where the common electrode 12 and the segment electrodes 13, 13...
It has a contrast of about 15: 1.

Therefore, in the finder panel 7 of the camera to which the liquid crystal panel P is applied, an image of the subject can be seen under a photographing condition such as when the subject is extremely bright, when the background is dazzling like a snow scene, or when the subject is backlit. When it is difficult, an appropriate voltage is applied to the segment electrode 13 to increase the light scattering degree of the liquid crystal in that portion to enhance the contrast so that the subject can be viewed well with appropriate brightness. it can. This makes it possible to easily focus on the subject even under the above-described shooting conditions.

Next, referring to FIGS. 3 to 7, the segment electrodes 13 (13a, 13b, 13c, 1) of the liquid crystal panel P will be described.
An example of the arrangement pattern of 3d) will be described.

First, in the example shown in FIG. 3, a transparent segment electrode 13 made of ITO or the like having a slit-like waveform is used.
are vertically arranged, and the individual electrodes are electrically insulated through narrow gaps or insulating materials.

The switching elements 15, 1 such as transistors are connected to the ends of the respective segment electrodes 13a.
Are provided, and are connected to a driver 16 with a selector via the switching elements 15, 15,....

The driver 16 selects the segment electrode 13a to which the voltage is to be applied based on the operation of the selection button 8 (for example, every other or every two based on the number of times the button 8 is pressed). Then, based on the operation of the contrast adjustment button 9, a predetermined voltage is applied to the selected segment electrode 13a (for example, the voltage is gradually increased each time the contrast adjustment button 9 is pressed) to increase the contrast. The amount of change can be changed appropriately.

Therefore, when the subject is extremely bright when looking through the viewfinder, or when the subject is difficult to see and focus under the photographing conditions where the background is dazzling, the segment electrode 13a is set to be alternate. Alternatively, you can select every third or adjust the applied voltage to change the contrast by an appropriate amount so that you can view the subject with appropriate brightness, making it easier to focus Will be able to do it. In FIG. 3,
A broken line 17 indicates a range that can be actually seen on the finder panel 7.

The shape of the waveform of the segment electrode 13a is not limited to the one shown in the figure, but may have a finer wave or a gentler wave, and the number of electrodes provided is not particularly limited. Instead, more or less may be used.

In the example shown in FIG. 4, the segment electrodes 13a, 13a... Having the same waveform as those shown in FIG. Nine are provided side by side. Each segment electrode 13a, 1
The switching elements 1 similar to FIG.
Switch array S composed of 5, 15,... And driver 1
6 are provided.

In the embodiment shown in FIG. 4, the portion where the contrast can be changed is limited as compared with the embodiment shown in FIG. 3, but the number of segment electrodes and switching elements can be reduced, so that the manufacturing cost can be kept low. it can. Further, a segment electrode may be provided via two or more gaps 18.

In the example shown in FIG. 5, instead of the waveform shape shown in FIG. 3, a vertical stripe is formed in which twenty transparent segment electrodes 13b, 13b... The individual electrodes are electrically insulated through narrow gaps or insulating materials.

In the example shown in FIG. 6, thirteen strip-shaped segment electrodes 13c, 13c... Are arranged side by side to form a horizontal stripe, and the individual electrodes are electrically connected via a gap or an insulating material. Are electrically insulated. Further, instead of the strip shape, segment electrodes having a waveform as shown in FIG. 3 may be arranged horizontally as shown in FIG.

Further, in the examples shown in FIGS. 5 and 6, the segment electrodes 13b and 13c may be arranged alternately with a gap having a predetermined width as described with reference to FIG.

In the example shown in FIG. 7, concentric segment electrodes 13d, 13d,... Are electrically insulated via a gap or an insulating material. Note that the number, width, and the like of the concentric segment electrodes 13d can be arbitrarily determined. Alternatively, the segment electrodes 13d may be arranged alternately via a concentric gap having a predetermined width.

Referring now to FIGS. 8 and 9, a description will be given of a configuration example of a circuit for driving the liquid crystal panel P having the above-described segment electrodes 13 and a driving waveform example. In the present embodiment, the driving method of the liquid crystal panel P is not particularly limited, but a static driving method is adopted.

In FIG. 8, 8 is a selection button for selecting a segment electrode, 9 is a contrast adjustment button,
Reference numeral 20 denotes a controller IC, and reference numeral 16 denotes a driver with a selector. The controller IC 20 controls the driver 16 to apply a desired voltage to the common electrode 12 and the segment electrode 13 of the liquid crystal panel P to change the contrast of the liquid crystal, and uses a microcomputer LSI such as a single chip microcomputer. Can be configured.

The driver 16 is connected to the common electrode 12 of the liquid crystal panel P and the segment electrodes 13 through the switch array S composed of the switching elements 15, 15,.
13...

The waveform of the voltage applied to the common electrode 12 and the segment electrode 13 via the controller IC 20 is, for example, as shown in FIG.

In FIG. 9, (a) is a voltage waveform applied to the common electrode 12, (b) is a voltage waveform applied to the switching element 15 of the segment electrode 13 to be turned on, and (c) is a segment to be turned off. The voltage waveform applied to the switching element 15 of the electrode 13, (d) is the voltage waveform actually applied to the liquid crystal 11 via the on-segment electrode 13, (e) is the voltage waveform actually applied to the liquid crystal 11 in the off state FIG.

As shown in the drawing, a voltage having a waveform opposite to the waveform of the common electrode is applied to the segment electrode 13 whose light scattering is to be changed, and a voltage having a waveform opposite to that of the common electrode is applied to the segment electrode 13 whose light scattering is not desired. A waveform voltage is applied.

By operating the contrast adjustment button 9, the voltage applied to the liquid crystal 11 via the common electrode 12 and the segment electrode 13 is changed from V 1 to V
2, which can change the degree of light scattering and adjust the overall contrast.

Therefore, in order to change the contrast of the liquid crystal panel P by the driving circuit having the above configuration, the photographer first checks the subject in the viewfinder, and when the subject is too bright or the background is dazzling. By operating the selection button 8 (for example, pressing the button a predetermined number of times), the segment electrode 13 to which a voltage is applied is selected. Specifically, for example, when the selection button 8 is pressed once, the segment electrodes 13 to which the voltage is applied can be selected every other one, and every other two.

The photographer operates the contrast adjustment button 9 while checking the appearance of the subject to adjust the voltage applied to the selected segment electrode 13.
Adjust so that the subject is easy to see. Thereafter, the photographer focuses on the subject, sets a shutter speed, an aperture value, and the like, and presses the shutter button to execute photographing.

As described above, the liquid crystal panel P according to the present embodiment
According to the viewfinder panel using, even if the subject is extremely bright, the background is dazzling like a snow scene, or the subject is difficult to see due to backlight etc., the position of the subject can be freely contrasted , The subject can be satisfactorily confirmed with appropriate brightness, and focusing can be easily performed.

In the above embodiment, the case where the liquid crystal panel according to the present invention is mainly applied to a finder panel of a single-lens reflex camera has been described. However, the present invention is not limited to this. For example, microscopes, binoculars,
The present invention can be applied to a finder of a wide range of optical devices such as a telescope.

The use of the liquid crystal panel according to the present invention is not limited to a finder panel, and the liquid crystal to be enclosed is not particularly limited to a polymer dispersed liquid crystal (PDLC).

In the above embodiment, the case where the static driving method is used as the liquid crystal driving method has been described. However, the present invention is not limited to this. For example, the electrodes can be driven by the multiplex driving method to adjust the contrast. Can also be configured.

Further, in this embodiment, the case where the photographer judges the brightness of the subject and the background with his eyes and manually adjusts the light scattering of the liquid crystal panel P has been described.
It is also conceivable that the illuminance of the subject or the background is detected by a photo sensor or the like, and the light scattering of the liquid crystal panel P is automatically adjusted based on the detection result to optimize the brightness of the subject in the finder. Can be

[0047]

As described above, according to the present invention, in a liquid crystal panel having a liquid crystal layer sandwiched between a pair of transparent substrates, a transparent electrode for driving liquid crystal is provided on an inner surface of each of the transparent substrates, The transparent electrode of one transparent substrate is divided into a plurality of strips, and the state of the liquid crystal layer can be changed by appropriately changing the voltage applied to each strip-shaped transparent electrode. If applied to the finder panel of the optical device, the voltage applied to each strip-shaped transparent electrode of the liquid crystal panel is adjusted to appropriately change the degree of light scattering of an image of an object or background seen through the liquid crystal panel. For example, when the background is dazzling like a snow scene, the contrast can be increased by adjusting the liquid crystal panel so that the light scattering degree becomes strong,
There is an effect that focusing can be easily performed.

The liquid crystal layer can be composed of a polymer dispersed liquid crystal in which a polymer is dispersed in a liquid crystal layer composed of liquid crystal molecules. In this case, depending on the characteristics of the polymer dispersed liquid crystal, Since it is not necessary to provide a polarizing plate on the transparent substrate, there is an effect that the inside of the finder can be made bright and easy to see.

Further, the plurality of strip-shaped transparent electrodes can be selected alternately or alternately so that a voltage is applied only to the transparent electrodes, or they can be formed at predetermined intervals. In this case, the configuration can be simplified and the power consumption can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a configuration example of a camera to which a liquid crystal panel according to the present invention is applied.

FIG. 2 is a longitudinal sectional view showing a schematic configuration of a liquid crystal panel according to the present invention.

FIG. 3 is a plan view illustrating an arrangement pattern of segment electrodes of the liquid crystal panel according to the present invention.

FIG. 4 is a plan view illustrating another arrangement pattern of the segment electrodes of the liquid crystal panel according to the present invention.

FIG. 5 is a plan view illustrating another arrangement pattern of the segment electrodes of the liquid crystal panel according to the present invention.

FIG. 6 is a plan view illustrating another arrangement pattern of the segment electrodes of the liquid crystal panel according to the present invention.

FIG. 7 is a plan view illustrating another arrangement pattern of the segment electrodes of the liquid crystal panel according to the present invention.

FIG. 8 is a block diagram showing a configuration example of a driving circuit of a liquid crystal panel according to the embodiment.

FIG. 9 is a block diagram showing a driving waveform example for the liquid crystal panel according to the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Camera main body case 2 Shooting lens 3 Film 4 Reflection mirror 5 Pentaprism 6 Eyepiece lens 7 Finder panel 8 Select button 9 Contrast adjustment button 10a, 10b Transparent glass plate (transparent substrate) 11 Mixture of polymer substance and liquid crystal (PDLC) 12 common electrode 13 (13a, 13b, 13c, 13d) segment electrode (band-shaped transparent electrode) 14 sealing member 15 switching element (switch array S) 16 driver 20 controller IC P liquid crystal panel

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Keiji Jingu 3-3-5 Yamato, Suwa-shi, Nagano Seiko Epson Corporation (72) Inventor Tomio Sonehara 3-5-2-5, Yamato, Suwa-shi, Nagano Seiko -Within Epson Corporation (72) Inventor Shuji Ikukawa 3-3-5 Yamato, Suwa City, Nagano Prefecture Seiko-Within Epson Corporation

Claims (8)

[Claims] In a liquid crystal panel having a liquid crystal layer sandwiched between a pair of transparent substrates, a transparent electrode for driving liquid crystal is provided on an inner surface of each of the transparent substrates, and at least one of the transparent substrates has a plurality of transparent electrodes. A liquid crystal panel, wherein the liquid crystal panel is divided into strips, and the state of the liquid crystal layer can be changed by appropriately changing the voltage applied to each strip-shaped transparent electrode. 2. The liquid crystal panel according to claim 1, wherein the liquid crystal layer is composed of a polymer dispersed liquid crystal in which a polymer is dispersed in a liquid crystal layer composed of liquid crystal molecules. 3. The method according to claim 1, wherein the plurality of band-shaped transparent electrodes are selected every other or every plural number, and a voltage can be applied only to the transparent electrodes. LCD panel. 4. The liquid crystal panel according to claim 1, wherein the strip-shaped transparent electrodes are formed at predetermined intervals. 5. The plurality of strip-shaped transparent electrodes are formed as strip-shaped vertical stripes or horizontal stripes having the same width in the horizontal direction or the vertical direction. 5. The liquid crystal panel according to any one of 4. 6. The method according to claim 1, wherein the plurality of strip-shaped transparent electrodes are formed as wavy vertical stripes or horizontal stripes formed in a horizontal direction or a vertical direction. Liquid crystal panel according to Crab. 7. The liquid crystal panel according to claim 1, wherein the plurality of strip-shaped transparent electrodes are configured to be concentric. 8. A liquid crystal panel according to claim 1, wherein the liquid crystal panel is provided as a finder panel, and a voltage applied to each strip-shaped transparent electrode of the liquid crystal panel is adjusted to adjust a voltage applied to a subject or the like which is seen through the liquid crystal panel. An optical device characterized by being configured to be able to appropriately change the degree of light scattering of an image such as a background.