JPH0283535A - Image information converting element - Google Patents

Abstract

PURPOSE:To obtain the high sensitivity and the large electrooptic effect of the subject element by composing a light modulation layer member of a light modulation material comprising a combination of an org. nonlinear optical material of MNA (2-methyl-4-nitroaniline) and a liquid crystal. CONSTITUTION:The title element is constituted of a laminated obtd. by interposing at least an photoconductive layer member 25 and the light modulation layer member 28 between two sheets of transparent electrodes 23, 24. The member 28 is composed of the light modulation material comprising the combination of the org. nonlinear optical material of MNA and the liquid crystal. Namely, as the member 28 is solidified in a state of being oriented a liquid crystal molecule, and also the MNA combined to the liquid crystal molecule is a state of being oriented, the high sensitivity and the large contrast ratio of the element are obtd. by using the MNA having large nonlinear optical contrast ratio for the element.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image information conversion element suitable for imaging devices, optical writing projection devices, and the like.

(Prior Art) As an image information conversion element configured to input an optical image and output an optical image as an output, for example,
There are various configurations such as spatial modulation elements such as liquid crystal type optical modulators, photoconductive Pockels effect elements, microchannel type optical modulators, etc., and elements constructed using photochromic materials. It has long been attracting attention as an optical writing projection device, an element for optical parallel processing in an optical computer, an element for recording images, and the like.

@ Figure 3 is a side sectional view showing an example of the configuration of a conventional image information conversion element. In the image information conversion element shown in Figure 3, 1 and 2 are glass plates, 3 and 4 are transparent electrodes, and 5 6 is a photoconductive layer member, 6 is a light shielding layer (light blocking layer), 7 is a dielectric mirror, and 8 is a liquid crystal (for example, a tweeter) as a light modulating material layer member that changes the state of light according to the intensity distribution of the applied electric field. This is an example in which a steady nematic liquid crystal (steady nematic liquid crystal) is used, and the light modulating layer member 8 has alignment films 9 on both sides thereof.
10 are arranged. Further, 11 is an AC power supply, WL is a write light, and RL is a read light.

In the image information conversion element shown in FIG. 3, the voltage of the power source 11 is applied between the transparent electrodes 3 and 4 described above.

An electric field is applied between both ends of the liquid crystal layer (hereinafter sometimes referred to as liquid crystal layer 8) used as the light modulating material layer member 8, and the glass plate 1 side of one image information conversion element is When writing light WL is incident on the glass plate 1 and the transparent electrode 3 and reaches the photoconductive layer member 5, the electrical resistance value of the photoconductive layer member 5 becomes as follows. Since the charge image changes in accordance with the optical image caused by the incident light that has reached the photoconductive layer member 5, a charge image that corresponds to the optical image caused by the incident light that has reached the photoconductive layer member 5 is formed at the interface between the photoconductive layer member 5 and the light shielding layer 6. arise.

In the above state, between the transparent electrodes 3 and 4 to which the voltage of the power source 11 is applied, a light shielding layer 6, a dielectric mirror 7, etc. are provided in series with the photoconductive layer member 5. An electric field having an intensity distribution corresponding to the optical image formed by the incident light is applied to the liquid crystal layer 8 .

That is, the readout light R in a linearly polarized state is transmitted to the glass plate 2 side.
When L is projected, the projected readout light RL travels as follows: glass plate 2 -> transparent electrode 4 -> alignment film 10 -> liquid crystal M8 -> alignment film 9 -> dielectric mirror 7 -> light shielding layer 6. The part returns as reflected light to the glass plate 2 side by the FJff single body mirror 7, but since the optical axis of the molecules of the liquid crystal in the liquid crystal layer 8 is no longer parallel to the transparent electrode, the light returns to the glass plate 2 side as described above. When the readout light RL in the linearly polarized state is projected onto the nematic liquid crystal, the state of birefringence changes according to the electric field strength applied to the liquid crystal layer 8 due to the electro-optic effect of the nematic liquid crystal, thereby corresponding to the optical image described above. Reflected light whose polarization plane changes according to the charged image is generated, and optical image information corresponding to the optical image of the subject appears on the glass plate 2 side.

Then, as described above, the readout light RL is projected onto the glass plate 2 and travels as follows: transparent electrode 4 → alignment film 10 → liquid crystal layer 8 → alignment film 9 → dielectric mirror 7 → light shielding layer 6. Since the light that is not reflected by the dielectric mirror 7 is blocked by the light shielding layer 6 so that it does not proceed toward the photoconductive layer member 5 side, even if the readout light RL is projected onto the glass plate 2 side, the light is not reflected by the dielectric mirror 7. Since the electrical resistance value of the leading FFI layer member 5 will not change due to It does not change the generated charge image.

Therefore, by passing the elliptically polarized light emitted from the glass plate 2 side through the analyzer, the light passing through the analyzer exhibits a spatial intensity distribution corresponding to the optical image of the subject. Then, a third layer using liquid crystal as a light modulating material layer member is used.
In the image information conversion element having the configuration shown in the figure, a sensitivity of, for example, 5 μJ/d and a resolution of 50 Qp/mm can be obtained.

FIG. 4 is a side sectional view showing another example of the configuration of a conventional image information conversion element. In the image information conversion element shown in FIG. 4, 12 and 13 are transparent electrodes, and 14 is an insulating layer , 15 is known as a light modulating material that has both a photoconductive effect and a Pockels effect.
16 is a power source, WL is a writing light, and RL is a reading light.

In the image information conversion element illustrated in FIG. 4, the voltage of the power source 16 is applied between the transparent electrodes 12 and 13 described above, and the light modulating material layer member 15 is made of BSO (Bi12Si020). (hereinafter sometimes referred to as 880 layer 15), an electric field is applied between both ends of the 880 layer 15, and blue light is transmitted from the transparent electrode 13 side of the image information conversion element and red light is reflected. Short-wavelength writing light WL such as ultraviolet light or blue light is incident through the dichroic mirror 17, and the incident short-wavelength writing light WL is transmitted through the transparent electrode 13 and the insulating layer 14 to form 880 layers. 15, the 880 layer 15 absorbs the aforementioned short wavelength writing light, and the electrical resistance value of that layer decreases in accordance with the light intensity distribution of the writing light.

Since a constant voltage is supplied between the transparent electrodes 12 and 13 from the power supply 16 as described above, the electrical resistance value of the 880 layer 15 changes in response to the optical image created by the short wavelength writing light. A pattern emerges.

As a result, the voltage distribution between the insulating layer 14 and the 880 layer 15 described above changes in accordance with the optical image created by the short wavelength writing light.

When the linearly polarized readout light RL of the red light is made incident through the dichroic mirror 17 that reflects the red light from the transparent electrode 13 side of the image information conversion element described above, the input readout light of the red light is RL is transparent electrode 13 → insulating layer 14 → BSO layer 15 → transparent electrode 12
The light passes through the optical path of and exits from the transparent electrode 12 side, but while this light passes through the 880 layer 15 having the Pockels effect, the plane of polarization changes according to the voltage pattern of the 880 layer 15. Therefore, when the light emitted from the transparent electrode 12 is passed through the analyzer as described above, the light that has passed through the analyzer will show a spatial intensity distribution corresponding to the optical image of the subject. . As shown in this fourth figure, in an image information conversion element having a configuration in which BSO is used as a light modulating material layer member, for example, 0.5 to 600 μJ/a
A resolution of 150 Qp/mm can be obtained with a sensitivity of 1.

(Problems to be Solved by the Invention) In the conventional image information conversion element described with reference to FIGS. 3 and 4, the liquid crystal and BSO used as the light modulating material layer member are as follows. In general, there is a drawback that the electro-optical effect is small and the sensitivity is low, and the image information conversion element using BSO as the light modulating material layer member described above requires short wavelength writing light WL such as ultraviolet light or blue light. Besides being done.

The problem is that the BSO exhibits a photoconductive effect even with respect to the red light used as the readout light RL, so non-destructive readout is not possible.

Furthermore, the above-mentioned image information conversion element using liquid crystal as the light modulating material layer member has the advantage that large-sized image information conversion elements can be easily manufactured because liquid crystal is used.
A problem with liquid crystals is that their response time is long, for example, 20 milliseconds to 500 milliseconds.

The disadvantage of liquid crystal, BSO, etc. used as light modulating material layer members in conventional image information conversion elements is that they have a small electro-optic effect and low sensitivity. Since this problem can be solved by using a large material, attempts have been made to use organic nonlinear optical materials, which in principle have a nonlinear optical constant 2.3 orders of magnitude higher than inorganic materials, as light modulating material layer members in image information conversion elements. It was done.

However, it is difficult to create stable and large single crystals of organic nonlinear optical materials, and even though each molecule has significant nonlinearity, it is difficult to crystallize them so that they have central symmetry during single crystallization. By this, large nonlinearities, ie.

The drawback was that the large electro-optic effect disappeared.

(Means for Solving the Problems) The present invention provides an image information conversion element having a laminated structure of at least a photoconductive layer member and a light modulation layer member between two transparent electrodes. hand.

The present invention provides an image information conversion element constructed using a light modulating material in which MNA (2-methyl-4-nitroaniline), which is an organic nonlinear optical material, and liquid crystal are combined as the light modulating layer member. .

(Example) Hereinafter, specific contents of the image information conversion element of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a side sectional view showing one embodiment of the image information conversion element of the present invention, and in the image information conversion element shown in FIG.
2 is a glass substrate, 23 and 24 are transparent electrodes (e.g. Nesa film), and 25 is a photoconductive layer member (~5 micron thick CdS
26 is a light blocking layer (a CdTe film with a thickness of ~1 micron), 27 is a dielectric mirror (for example, an alternating film of MgF2 film and ZnS film (a film thickness of ~2 μm and 15 layer)).

28 is a light modulating material layer member that changes the state of light according to the intensity distribution of the applied electric field, and this light modulating layer member 28
is an organic nonlinear optical material MNA (2-methyl-4
- Nitroaniline) and liquid crystal are combined using a light modulating material, and the structural formula of the light modulating material is illustrated in FIGS. 2(a) and 2(f).

29, 30 oriented [(for example, a 5 ioz obliquely deposited film with a thickness of ~2000 angstroms), 19 is a spacer, 18 is a power supply that supplies a predetermined voltage between the transparent electrodes 23 and 24 described above, and 20 is an antireflection film (eg, MgF2 film), WL is writing light, and RL is reading light.

The image information conversion element shown in FIG. A transparent electrode 24 and an alignment film 30 are sequentially formed on the other surface of a glass substrate 22 to which an antireflection film 20 is attached, and an endless strip-shaped spacer 19 is sandwiched between the alignment films 29 and 30. , alignment films 29 and 3 arranged opposite to each other.
0 and the spacer 19, MNA (2-methyl-4
- A light modulating material made by combining (nitroaniline) and liquid crystal is melted and injected, and then an alternating current voltage is applied between the transparent electrodes 23 and 24 to apply an alternating electric field to the light modulating material. Below, when the light modulating material is slowly cooled by decreasing the temperature of the light modulating material by 0.1° C. per hour until the light modulating material changes from the isotonic phase to the crystalline state, the alignment films 29 and
In the space surrounded by 30 and spacer 19,
The light modulating material layer member 28 is composed of a light modulating material in which MNA (2-methyl-4-nitroaniline), which is the organic nonlinear optical material described above, and liquid crystal are combined.

Then, MNA (2
-Methyl-4-nitroaniline) and liquid crystal are combined, and the light modulating material layer member 28 is made of a light modulating material in which liquid crystal molecules are oriented by an alternating current electric field applied during the slow cooling process as described above. MNA (2-
Methyl-4-nitroaniline) is also oriented in accordance with the orientation of the liquid crystal.

In the case where the materials and film thicknesses of each component in the image information conversion element of the present invention are as described above, that is, the photoconductive layer member (Cd5WJ with a thickness of ~5 microns) 25, the light shielding layer (light blocking layer) ...~1 micron thick Cd
T e film)26. Dielectric mirror (e.g. MgF2 film and Z
Alternating films with nS films (15 layers with a film thickness of ~2 microns) 2
It is constructed using 7.

Further, the image information conversion element of the present invention is configured using a light modulating material in which MNA (2-methyl-4-nitroaniline), which is an organic nonlinear optical material, and liquid crystal are combined as the light modulating material layer member 28. Characteristics of one example are shown in Table 1 below, corresponding to Example 1.

In addition, the materials and film thicknesses of each component in the image information conversion element of the present invention are as illustrated below, including a photoconductive layer member (α-5i with a thickness of ~5 microns) 25, a light shielding layer (light shielding layer) Blocking layer...~1 micron thick Si film) 26
, a dielectric mirror (for example, an alternating film of TiO2 film and 5i02 film (15 layers with a film thickness of ~2 microns)) 27 is used, and MNA, which is an organic nonlinear optical material, is used as the light modulating material layer member 28. The characteristics of other embodiments of the image information conversion element of the present invention constructed using a light modulating material in which (2-methyl-4-nitroaniline) and liquid crystal are combined are shown in Table 1.
This figure corresponds to Example 2 in the figure.

The conventional example shown in Table 1 is a liquid crystal light valve.

Now, in the image information conversion element of the present invention shown in FIG.
An electric field is applied between both ends of the light modulation layer member 28, which is made of a light modulation material combining (4-nitroaniline) and liquid crystal, and from the glass substrate 21 side of the image information conversion element. The writing light WL is incident on the glass substrate 21 and the transparent mold t7J.
When the photoconductive layer member 25 is transmitted through M23 and reaches the photoconductive layer member 25, the electrical resistance value of the photoconductive layer member 25 changes corresponding to the optical image of the incident light that has reached it. At the interface with the layer 26, a charge image corresponding to the optical image caused by the incident light reaching the photoconductive layer member 25 is generated.

In the above state, between the transparent electrodes 23 and 24 to which the voltage of the power source 18 is applied, a light shielding layer 26, a dielectric mirror 27, etc. are provided in series with respect to the photoconductive layer member 25. M is an organic nonlinear optical material that
The light modulation layer member 28 is configured using a light modulation material in which NA (2-methyl-4-nitroaniline) and liquid crystal are combined.

An electric field with an intensity distribution corresponding to the optical image created by the incident light is applied.

Therefore, when the readout light RL in a linearly polarized state is projected onto the glass substrate 22 side, the projected readout light RL is transmitted through the antireflection film 20→glass substrate 22→transparent electrode 24→alignment film 30.
→MNA (2-methyl-4-
The light modulating layer member 28, which is constructed using a light modulating material combining (nitroaniline) and liquid crystal, travels as follows: alignment [29] → dielectric mirror 27 → light shielding layer 26, and most of the light is The readout light RL returns to the glass substrate 22 side as reflected light by the dielectric mirror 27, but this readout light RL combines MNA (2-methyl-4-nitroaniline), an organic nonlinear optical material with an electro-optic effect, with the liquid crystal. Since the plane of polarization changes in accordance with the electric field caused by the charge image described above while passing through the light modulation layer member 28, which is constructed using a light modulation material that has been When the light emitted from the antireflection film 20 on the side of the transparent electrode 22 is passed through the analyzer, the light that has passed through the analyzer exhibits a spatial intensity distribution corresponding to the optical image of the subject.

(Effects of the Invention) As is clear from the above detailed explanation, the image information conversion element of the present invention has a laminated structure of at least a photoconductive layer member and a light modulation layer member between two transparent electrodes. MNA, which is an organic nonlinear optical material, is used as the light modulation layer member in the image information conversion loss element configured with
(2-Methyl-4-nitroaniline) combined with liquid crystal, the image information conversion element of the present invention uses MNA (2-methyl-4-nitroaniline), which is the organic nonlinear optical material described above, and a liquid crystal. The light modulating material layer member 28 is made of a light modulating material in which methyl-4-nitroaniline) and liquid crystal are combined.
Since the liquid crystal molecules are solidified in an oriented state, the MNA (2-methyl-4-nitroaniline) bonded to the liquid crystal molecules is also oriented and has a large nonlinear optical constant. MNA (2-methyl-4
-nitroaniline) provides a high sensitivity and a high contrast ratio.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal side view showing a schematic configuration of an embodiment of the image information conversion element of the present invention, and FIG. 2 is a combination of MNA (2-methyl-4-nitroaniline), an organic nonlinear optical material, and liquid crystal. FIGS. 3 and 4 are longitudinal sectional side views showing the schematic structure of an embodiment of a conventional image information conversion element. 1.2...Glass plate, 3, 4, 12, 13, 23°2
4... Transparent electrode, 5, 25... Photoconductive layer member, 6.
...26 light blocking layer (light blocking layer), 7,27...
Dielectric mirror, 8... Light modulating material layer member, 9, 10, 2
9゜30...Alignment film, 11...AC power supply, WL...
・Writing light, RL...Reading light, 14...Insulating layer,
15... Light modulating material layer member constructed using BSO, 1
6...Power supply, 17...Dichroic mirror 18
...Power source, 20...Anti-reflection film, 21.22...
Glass substrate, 28... MN which is an organic nonlinear optical material
A light modulating material layer member configured using a light modulating material in which A (2-methyl-4-nitroaniline) and liquid crystal are combined, W
L...Writing light, RL...Reading light, Patent applicant: Victor Japan Co., Ltd. γ

Claims (1)

[Claims] An image information conversion element configured with a laminated structure of at least a photoconductive layer member and a light modulation layer member between two transparent electrodes, the above light modulation layer member comprising:
An image information conversion element characterized by using a light modulating material in which MNA (2-methyl-4-nitroaniline), which is an organic nonlinear optical material, and liquid crystal are combined.