JPS5868017A - Picture transducer - Google Patents

Abstract

PURPOSE:To perform reading while suppressing the formation of film interference fringes by providing a reflection preventing film between a crystal plate having an electrooptic effect and a photoconductive effect depending upon wavelengths in combination and an insulation layer, and further providing the 2nd reflection preventing film on the outer side of a transparent electrode respectively in specified relations. CONSTITUTION:A crystal plate 1 is formed by using a single crystal of bismuth silicon oxide or the like, and insulation layers 4, 5 are provided on the outer sides of plates 2, 3. Transparent electrodes 6, 7 are provided on the outer sides of the layers 4, 5. A reflection preventing film 10 is provided between the plate surface 3 and the layer 5, and further a reflection preventing film 11 is provided on the outer side surface of the electrode 7. A voltage is applied to the electrodes 6, 7, and writing light L1 is irradiated thereto, whereby picture information is written. Readout light L2 is made incident perpendicularly to the surface 2 and the passed light is applied to an analyzer. The refractive indices of the layer 5, the electrode 7 and the plate 1 are defined as n3, n2, ns and the optical film thicknesses of the layers 10, 11 are set at lambda/4 (lambda; wavelength of read out light). A material of (n3.ns)<1/2> refractive index is used as the layer 10, and a material of n2/n3 refractive index is used as the layer 11 when the optical film thickness of the electrode 7 is lambda/4, whereby the readout free from interference fringes is accomplished.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a three-dimensional image conversion element triplet using a crystal plate that has a conductive effect.

All image information is written by incoherent light.

VC. ．． J:V), an image conversion element of the above type which performs an incoherent self-coherent transformation is well known in the art.

In this type of image conversion element (hereinafter referred to as I'l''C element), each surface of the crystal plate is optically polished to a high degree of polish, mainly for the purpose of removing noise. λ/
It is common to achieve a flatness of about 2 to λ/10 (λ is the readout wavelength). In this case, both sides of the crystal plate have highly accurate parallelism.

When reading image information, a part of the readout light is completely reflected within the I']"C element, and since this readout light is cohesin light, interference fringes are generated and the 1'1" C
It becomes difficult to faithfully read out image information that has been written to the element.

The present invention is not based on the above-mentioned insight.

Simple configuration Vr:. ．． The object of the present invention is to provide an I'J'C element capable of suppressing the generation of interference fringes.

4- In the following, advantageous embodiments of the invention will be described in comparison with conventional 1'II'' C elements with reference to the drawings.

FIG. 1 is an explanatory diagram showing an example of a T']"C element according to the present invention, and this T'l"C element has a crystal plate 1.

The outside of each mutually parallel plane 2.3 in this crystal plate l (
The insulating layers 4 and 5 located at C and the outside 111 of the insulating layer 4.5
11 and transparent electrodes 6 and 7 provided thereon. As the crystal plate 1, a crystal having both an electro-optic effect and a wavelength-dependent photoconductive effect is used.

Special Nibismuth silicon oxide (Bi,, Si
n,,. ) Single crystal bismuth germanium oxide (B' I 2 Ge 02 o ) single crystals can advantageously be used.

i 1c Each transparent electrode 6.7 is 1 e.g. n203, Sn
It is composed of a thin film made of O3 or a composite thereof.

The insulating IPJ4.5 shown in FIG.
It is also possible to use a separate insulating layer located outside each side 2, 3 of the crystal plate 1.
1 and 5 are made of a transparent material that allows all light to pass through, such as polyparaquinrylene.

According to the present invention, a first layer 10, which serves as an anti-reflection film, is provided between the crystal plate surface 3 on the right side 1 in FIG. 1 and the insulating layer 5 opposite thereto.

Furthermore, a second layer l1 is provided outside the transparent electrode 7 located on the right side of the transparent electrode 7.
The layer 10 and the second layer 1l are also composed of a transparent material, the advantageous names of which will be exemplified below.

The surfaces 2.3 of the illustrated crystal plate 1 are formed parallel to each other, and the first layer 10, the insulating layer 5, the transparent electrode 7 and the second layer 11 also extend parallel to each other.

To use all the TTC elements configured as described above,
First, apply voltage to scheme ji6 and ji7 by power supply +2,
A potential gradient sound is generated on the crystal plate 1. Next, writing light "+" from an image information source is irradiated from the right side in FIG. 1 (of course, it may be from the left side) through the entire imaging optical system (not shown).

Incoherent light having a wavelength at which the crystal plate exhibits a photoconductive effect is used. In this way, if the entire writing light is irradiated, the potential gradient mentioned above will decrease in the part of the crystal plate that is not irradiated with the writing light depending on the form of the image information. ．． In 6 minutes, is the electric fs' slope 1? ,
In order to maintain the original state, a predetermined image intensity 't'ft is applied to the ITC element. It should be noted that the photoconductive effect of the crystal plate is modified so that the carriers that have undergone 1° flow out to the transparent electrode (- are blocked by the insulating layer 1.5).
,reactor.

:XF including in ;/j 114i ('ljo'41
i ka output T ICij , readout beams 1 and 2 with curved polarizers (not shown), r 'r An example of a C element (left) Shoot the fire.

It is sufficient to pass the C element T- through a J1 filter and a 1 m analyzer (1 not shown). Coherent light with a wavelength that does not cause a photoconductive effect in the crystal plate 2 is used as the read light. In this way, one image information is interlined and at one time incoherent information is used, and when read out, it becomes coherent.
'C: fLI [1 Image information of each parrot's stomach and 5 pieces of coherent light 1111i image information (C conversion-4- can be obtained, this work 1 'II'
This is a 1-cohere/1...coherent conversion using a C element. Such I'1゛C element -f-Vl, P'1lij'
7- IJ 工 i exchange 'lo Maruji information processing l'il! It can be used to advantage of A vC.

Just like I did above, I rebelled ;)l: )7\datta picture 1
1: Read information 7- Finally, the generation of interference fringes due to the reflection of the readout light within the element is greatly suppressed.On the contrary, in the conventional T i' C as shown in FIG. As explained above, the occurrence of interference fringes is unavoidable in the element.

That is, in the element shown in FIG. 2 1, the first layer 10 and the second layer 11 shown in FIG. -c When trying to emit this light, some of the light is shown by the broken line in Figure 2]
As shown by 2', the boundary W plane I3C between the crystal plate 1 and the insulating layer 5
This reflected light 1 and 2' is reflected again at the boundary 5♀ then 14 between the crystal plate 1 and the insulating layer 4 on the other side, as indicated by the dashed line arrow.
3), because this was emitting from the JTC element.

When the parallelism of both surfaces 2 and 3 in the crystal plate 1 is good,
The reflection is carried forward and the light exits the T'I''C element, and is called light L3.
Interference fringes are generated by the light emitted from the element without being reflected, and based on this generalization, the first
The inconvenience explained in '11. Nakatsu friend.

In the configuration shown in No. 1N, it is possible to prevent the reflection of light as described above and to suppress the generation of interference fringes by VrC, and the specific conditions 8 and 1 are as follows. The method used to determine this will be explained in detail.

Figure 3 shows crystal plate 1. First layer10. Insulating layer 5, transparent electrical contact 7
FIG. 2 is an explanatory diagram schematically showing the entire state of the first blue layer of the second layer 11. FIG. No.: d4Id3・d2・d, il− shown in the figure
,,I.

The total thickness of each layer (+0, 5, 7, II) is represented by L, n, , n4, n, , +1. , ,
n, , and n. For example, crystal plate l, each layer (to, 5, 7
．． II), and the refractive index of the air 15 with respect to the reading light wavelength (where λ is the wavelength of light). And in the configuration according to the present invention.

By making the refractive index of each layer (To, 5, 7, 11) have a predetermined relationship, all 11 of the readout light that has passed through the crystal plate l can pass through each layer (+0.5, 7, +1) as it is. It is configured to pass through the trench and emit all of the TCC. In this case, as mentioned above, the readout light is applied to each layer (+0, 5
, 7, 11) to make it transparent.
One condition is the optical thickness d, ·n of the insulating layer 5.

It is also possible to determine this by setting the value to a predetermined extremely small size. However, the insulating layer 5 has a crystal plate l.
11-; node, that is, ++1'! It is necessary to set the thickness to such a value that no edge breakage will occur, and this thickness d3 is usually set at about several/ZITI to several tens of μm c-)f'L. Therefore, this At
Considering this, it is difficult to set the optical film thickness d3·n3ti of the insulating layer 5 to a predetermined extremely small size.

In the present invention, in view of this point, the optical film types n4·d, , n,·d of the first layer 10 and the second layer 1] and the optical film types n2·d2 of the transparent electrode 7 are , i.e. n, -d, = n, e d4-λ/4
(t)n2*d,, -λ/4 or (2)n
,, *d,, -λ/2
(3), and when the thickness d3 of the insulating layer 5 is set to any size, almost all the readout light is transmitted to each layer (5).
, 10, 7, and 11), the structure is such that the reflection filter t'' can be transmitted through the filter.The following 1.r.

Let me explain in detail.

(1) In general, the four layers shown in Figure 3 (+0.5°7
．． 11) Considering the case where light with wavelength λ and i is transmitted at an incident angle α, the matrix corresponding to n7 can be expressed as follows.

It is.

Therefore, one layer (Hl, 5, 7, 11)
, refractive index l]. If the matrix is expressed as equation (4), the light reflectance R of the entire four layers can be expressed as follows. .

fil) The matrix corresponding to the four layers (5, ], 0.7.1.1.) and its reflectance are generally expressed by equations (4) and (5). Then, n2・d2−
λ/4 [Let's consider the case of Type 21 offshore.

As mentioned above, the readout light is coherent parallel light, and ■T
Since the angle of incidence on the C element is substantially 00, the score (4
), the following seven trixes are obtained.

Here, if It - (l, the readout light that has passed through the crystal plate l will pass through the four layers (10, 5, 7, II), and no interference fringes will be generated. Therefore, 1 % = 0
If we calculate n+-n+ffi from equation (7) under the condition that:

n4 = 57 pickles ζ (8) nl
−n2/F(9) is obtained. In this case, ns, n, and 13 are unambiguous depending on the materials of the crystal plate l, insulating layer 5, and transparent electrode 7 to be used.
The first layer] 0 and the second layer so as to almost satisfy the equation and (9).
If the quality of layer 11 is selected, F'L2 is made zero, and the generation of interference fringes can be greatly suppressed.

For example, a Bi...
) When all the transparent electrodes 7 are used, In, ,
(A composite of J3 and S n03 is composed of 3 [3], a polyparaquinoleno film is used as the insulating layer 5, and t is a crystal plate] (+380 single crystal) refractive index ns u 2.53
Similarly, [n2=2°0, n3=1.63, so according to equations (8) and (9).

n, ri 2.03
(10n1 ri1..57
(1◇ is obtained. In such a case, the first layer]0 is, for example, zirconia (n4
"21)t As the second layer 11, for example, cerium fluoride (n+"1.6) can be used as a combination of the 00 type and 0]) type.

Then, by substituting these values into equation (5) to find the reflectance R, this f (if
0, 5, 7, II) can be suppressed to a very small degree, and the generation of interference fringes can be effectively suppressed. Visit,
It is desirable that the first layer 10 (g) has high insulating properties in order to prevent the carriers generated in the crystal plate 1 together with the insulating layer 5 from flowing out to the transparent electrode. If a material with a low heat resistance of 11'', such as polyvaraxylylene, is used as the twisted insulating layer 5, this requirement can be met without any problem because it has a specific volume resistivity.

[There is a risk that the absolute R layer may deteriorate due to heat and break off during the production of the TC element. That is, when the first layer 10 and the transparent electrode 7 are formed by steam blue, the crystal plate 1 is also heated and the insulating layer 5 is likely to deteriorate.
This is the reason. However, when forming the first layer 10 made of, for example, a zirconia thin film by vapor deposition, the insulating layer 5 has not yet been formed, so there is no risk of deterioration of this, and the transparent electrode 7 is vapor-deposited on the insulating layer 5. When doing so,
If the ion blating method is fully adopted, there is no need to heat the oven to the extent that the insulating layer 5 deteriorates. If the second layer 11 is made of, for example, cerium fluoride, the deterioration of the insulating layer can be completely prevented.

However, when the second [*11] is soft-coated in this way, the ■TC element constructed as described above is sandwiched between a transparent glass substrate coated with a reflective anti-corrosion film for the purpose of preventing its peeling. It is desirable to contain it. By taking measures in this way, it is possible to prevent thermal deterioration of M-type insulators such as polyparaxylylene films, and also to prevent the insulating properties of the shredded insulating layer from absorbing moisture and reducing its insulation properties.
Safety is also maintained when the full high voltage is applied to the crystal plate.

(il[l-order IF,, n2@d2−λ/2[(3)
Consider the case where the expression is set. In this case also n2・
Using exactly the same method as described above when d2-λ/4.

When we find n, , n, which satisfy R-0, we get n, -
“Slow 0an4=,1
113.na H is obtained.

Therefore, crystal plate 1. Readout light, transparent electrode7. Assuming that the insulating layer 5 is exactly the same as that shown in the example of (i[C), n2'''2.53. n252.0. n3
-=f1.63, (from formula 19 and formula 03,
Therefore, in this case as well, the first layer 10 is made of, for example, siliconia (n4
For example, magnesium fluoride (A/1.38) can be used as the second layer 11, and the reflectance at that time can also be suppressed to 0.5 or less. Similarly, in this case as well, in order to completely prevent deterioration of the insulating layer 5 due to heat, I'I'
It is advantageous to fabricate the entire C element, in which case the second layer 1]
Although it is desirable that the magnesium fluoride film is also made into a soft coat, in this case as well, it is advantageous to sandwich the TTC element between transparent glass substrates coated with a total anti-reverse film.

To summarize the matters explained in (11) and GiD above.

(1) il@Io;n4=7elHY satisfies 1, preferably a material having a high specific volume resistivity is formed with an optical film thickness of λ/4 to obtain 10 layers per layer.

(2) Second layer ++; n2-d2=λ/4 full 7
'll ki l'c[.

n, = n2/Jna k is almost gone, n,, ad2
When is λ/2, the optical film thickness n1・d is λ/4 for a material whose nearness rate n1 is almost full.
A second layer II is obtained by forming the second layer II.

By configuring as shown below, the reflection of Q) light inside the I'l'C element can be suppressed, and therefore the generation of interference fringes can be made small enough to be ignored.

However, the present invention is not limited to the embodiment shown in FIG. 1, and can be modified in various ways.For example, as shown in FIG. 4,
Both sides of the crystal plate l (1111Il) have the first (1) layer 10 and the second
It is also possible to provide a layer 11 of. The present invention can also be advantageously applied to an ITC element in which an insulating layer is provided only on the outside of one surface of a crystal plate.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram showing an example of an ITC element according to the present invention, and Fig. 2 is an explanation (support) showing an example of a conventional ITC element.
, FIG. 3 is an explanatory diagram further schematically showing a part of the ITC element shown in FIG. 1, and FIG. 4 is an explanatory diagram similar to FIG. 1 showing another example of leprosy. 1... Crystal plate; 4, 5... Insulating layer; 6.7...
Transparent electrode; 10...first layer; 11...second layer; l
,,n, ,n,, +"3"4...Refractive index diagram 1

Claims (4)

[Claims] (1) A crystal plate having both an electro-optic effect and a wave-dependent photoconductive effect, at least one side of the crystal plate (
An image conversion element including an insulating layer located at C and a pair of transparent electrodes for applying a voltage to the crystal plate. A first layer and a second layer are provided to prevent reflection of read light. The first layer is disposed between the crystal plate and the insulating layer, and the first layer is disposed between the first layer and the second layer. The second layer is arranged so that the insulating layer is in contact with the first layer, and the total wavelength of the readout is λ, and the first layer is adjacent to the insulating layer, and the one transparent electrode is , and ^11 of the crystal plate,
Refractive index for readout light wave? That's it, n3 + n2
+ ns, the optical film thickness of the first layer and the second layer is set to λ/4, and a material whose refractive index is approximately "par 1" is used as the first layer. When the optical thickness of the transparent electrode is λ/4, the second layer is made of a material whose refractive index is approximately n2/r. (2) The image conversion element according to claim 1, wherein the convex M8 self-crystal plate is made of bismuth oxide single crystal or bismuth germanium oxide single crystal. (3) A crystal plate having both an electro-optical effect and a photoconductive effect dependent on waves, an insulating layer located on at least one side of the crystal plate, and a pair of transparent electrodes for applying the π voltage to the crystal plate. In an image conversion element including 1. A first layer and a second layer are provided to prevent reflection of readout light; ^11 first layer gold;
and between the first layer and the second layer. The entire second layer is arranged so that one of the transparent electrodes of the pair of transparent electrodes is in contact with the insulating layer adjacent to the pole, and the readout light is One skin length is λ, and the refractive index of the insulating layer adjacent to the first layer, the one transparent N pole, and the crystal plate relative to the wavelength of the readout light is n n3 , n2.11
8, then the total thickness of the first layer and the second layer is λ/・
1 and a material whose refractive index is approximately 4n3·nS is used as the first layer, and when the round film thickness of the one transparent electrode is λ,/2, the second layer The image conversion element is characterized in that it uses a material whose refractive index is almost the same. (4) The image conversion element according to claim 3, wherein the crystal plate is made of a bismuth silicon oxide single crystal or (-r bismuth germanium oxide small crystal).