Light shutter device

Details Light shutter device Light shutter device

2000-07-12

2002-02-19

Gray, David M. (Department: 2851)

Photography

Camera detail

Shutter

C359S254000, C359S323000, C349S056000

Reexamination Certificate

active

06347894

ABSTRACT:

This application is based on application No. 11-200018 filed in Japan, the content of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a light shutter device, and more particularly to a light shutter device which has a plurality of light shutter elements on a substrate made of a material with an electro-optical effect and which controls turning-on and turning-off of the light by applying a voltage to the light shutter elements.
2. Description of Prior Art
There have been provided various kinds of light shutter devices to form an image on a silver salt print paper, a silver salt film or a photosensitive member. Such a light shutter device has arrays of light shutter tips made of PLZT, which has an electro-optical effect, and controls turning-on and turning-off pixel by pixel.
Specifically, as
FIG. 5
shows, when a voltage is applied to a pair of electrodes
32
and
33
provided on a light shutter tip
30
, birefringence by the PLZT of the light shutter tip
30
becomes possible. In this state, light which is incident to a light transmitting portion (light shutter element)
31
via a polarizer
35
is polarized by the PLZT at 90 degrees, and the light emergent from the light transmitting portion
31
passes through an analyzer
36
. In this way, light is turned on and off.
FIG. 6
shows an example of the electrode structure of a conventional light shutter tip. In the tip
30
, in two scan lines X to write one line, light shutter elements
31
a,
31
b, . . .
are arranged. On respective one sides of the light shutter elements, individual electrodes
32
a,
32
b,
. . . are provided, and on the other sides, a common electrode
33
which is connected to the ground is provided.
Such light shutter elements are driven with a half-wave voltage applied thereto so as to obtain the maximum light transmittance; however, crosstalk occurs between adjacent light shutter elements on each of the scan lines X, which fluctuates the light transmittance. For example, focusing on the element
31
c,
the light transmittance characteristic when only the element
31
c
is turned on is shown by the curve A in FIG.
7
. The curve B in
FIG. 7
shows the light transmittance characteristic of the element
31
c
when the neighboring elements are also turned on simultaneously with the element
31
c;
in this case, the light transmittance decreases. The light transmittance of the element
31
c
when a half-wave voltage is applied to the element
31
c
and the neighboring elements is approximately 10% lower than that when the half-wave voltage is applied only to the element
31
c.
In order to solve this problem, as
FIG. 8
shows and as Japanese Patent Laid Open Publication No. 60-159722 suggested, shield electrodes
34
a,
34
b . . .
which extend from the common electrode
33
to among the light shutter elements
31
a,
31
b . . .
are provided.
FIG. 8
shows only the part around one of the two scan lines X.
In this structure, however, the shield electrodes
34
a,
34
b . . .
and the individual electrodes
32
a,
32
b . . .
are very close to each other, and it is difficult to adapt this structure for a high-definition device. Also, large capacitance occurs among the individual electrodes and the shield electrodes, which results in an increase in electric power consumption. Moreover, as the shield electrodes are thinned, the effect becomes weak, and in this point, also, this structure is not suited for a high-definition device.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a light shutter device which inhibits crosstalk from occurring between adjacent light shutter elements, which can be adopted to achieve high definition and which does not increase electric power consumption.
In order to attain the object, a light shutter device according to the present invention comprises: a substrate made of a material with an electro-optical effect; a common electrode which extends in a specified direction on the substrate; a plurality of individual electrodes which are arranged by a side of the common electrode along the common electrode; and a plurality of light shutter elements which are located between the respective individual electrodes and the common electrode and which are driven by application of a voltage between the respective individual electrodes and the common electrode. In the light shutter device, the light shutter elements are arranged in such a way that adjacent light shutter elements are located in mutually different positions with respect to a direction perpendicular to the common electrode extending direction.
In the structure, since adjacent light shutter elements are arranged in mutually different lines in parallel to the common electrode extending direction, the distances among the elements are long. Therefore, the crosstalk among the elements is small, and the light transmittance of each element when all the elements are turned on is the same as that when only one element is turned on. Moreover, it is not necessary to provide shield electrodes among the elements, which means that adaptation for a high-definition device is possible and that the consumption of electric power does not increase.


REFERENCES:
patent: 4753517 (1988-06-01), Samek
patent: 4766445 (1988-08-01), Springer
patent: 4854678 (1989-08-01), Kitano et al.
patent: 5029989 (1991-07-01), Phillips
patent: 60-159722 (1985-08-01), None

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