JPS58105120A - Plzt optical switching array - Google Patents

Abstract

PURPOSE:To perform high-resolution, high-contrast switching by providing discretely plural switching electrodes on one surface of a PLZT base plate and a reflector 26 on the opposite surface. CONSTITUTION:A PLZT optical switching array 21 has a PLZT22 base plate. whose opposite surfaces 22a and 22b are polished optically to obtain an about 200mum thickness. On one surface 22a, plural switching electrodes 23 and 24 formed of Ni, Cr-Au, etc., by photoetching technique are provided discretely. An electric field E is produced in an optical switch area 25 when a voltage is applied between switching electrodes 23 and 24 scarcely as deep as a distance between the electrodes, but a reflector 26 made of metal is provided on the reverse surface 22b to retard light in a returning travelling and to compensate a decrease in contrast accompanied with high resolution.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a PLZT optical switching array, and particularly to a PLZT optical switching array that can provide high resolution and sufficient contrast.

Examples of conventional PLZT optical switching arrays include those shown in FIG. 1 or 2. PLzT
The optical switching array l is made of PbZrO3 (lead zirconate), pbTiod (lead titanate) and a small amount of La2O5.
Transparent and strong! On one side of the PLZT substrate 2a, which exhibits il conductivity, a photoetching technique was used to deposit Ni.
The structure is such that a switching pole 3 made of -Cr-Au or the like is provided. As shown in FIG. 1, switching $i3 and g are alternately arranged in parallel in a cross-finger pattern, or as shown in FIG. 1, switching w and pole μ are ltf On the other hand, a plurality of switching electrodes 3 are arranged parallel to each other and are arranged perpendicular to and spaced apart from the switching electrode μ. PLZT optical switching array/
Switching electrode 3. By controlling the voltage applied to μ, switching can be controlled between poles 3 and 4'.
Turns on and off the light that passes through.

FIG. 3 shows a conventional PLZT optical switching array applied to an optical printer. A PLZT optical switching array is placed between a polarizer t and an analyzer 7 disposed perpendicular to the polarizer 6, and the light from the mercury lamp t is converted into a parallel beam of light and the polarizer is irradiated from the side. Switching electrodes of Pi, ZT optical switching array l3. The light transmitted through the PLZT optical switching array l is analyzed by an analyzer 7 and irradiated onto a photosensitive paper 10.

By the way, the resolution of the PLZT optical switching array/3. It is determined by the polar pitch of ≠. Using current photoetching technology, 5
It is easy to form one set of t-poles with a pitch of 0μ, and with this pitch the switching electrodes 4M3. When 'l is formed, the resolution becomes 20 dots/h. Furthermore, it is possible to form switching electrodes at a higher density than this, and a PLZT optical switching array with higher resolution can be realized.

However, the conventional PLZT optical switching array l
In order to obtain high resolution, the electrode pitch is made opaque.
Switching electrode 3. If you form ≠ into a −”,
As shown in FIG. μ, the switching electrode 3. between ゛′
- The pole spacing l becomes smaller. On the other hand, switching [pole 3.
The effective edge d of the electric field E in the region j between μ is approximately j
Since switching electrode 3. The more densely the holes are formed, the smaller the effective depth d becomes. PLZ
Contrast of T optical switching array l (ON/'O
FF ratio) is 1 for the effective depth d when the electric field strength 1 length is constant.
There is a bar. Therefore, in the conventional PLZT optical switching array, the switching electrode 3 is
．． When the layers are formed in a high density, the effective depth d becomes small and the contrast becomes small.

An object of the present invention is to provide a PLZT optical switching array with high resolution and sufficient contrast.

The PLZT optical switching play of this invention is a PLZT optical switching play.
The present invention has a configuration i in which a plurality of switching electrodes are formed spaced apart on one surface of the substrate, and a reflector is formed on the other surface facing the one surface.

Hereinafter, the present invention will be explained with reference to the drawings.

FIG. j, t shows a part of a PLZT optical switching array and optical system according to an embodiment of the present invention. First, the configuration will be explained. 2/ indicates a PI, ZT optical switching array. PLZT optical switching array 2/
are PbZr05 (lead zirconate) and PbTi05 (
A transparent ferroelectric PLZT substrate (its composition is AV35) consisting of lead titanate) and a small amount of La205. (The composition of PLZT is generally (Pb1-xLax) (Z
rt-y 'rty) 03, but as an abbreviation C1
00x/100-100y/100y') is used. )) has 22. The PLZT substrate n has two λ surfaces facing each other, which are optically polished, and has a thickness of −00μ. On one side 22h of the PLZT substrate 2, N and Cr- are etched by photo-etching technology.
A plurality of switching electrodes made of Au or the like are provided spaced apart. For convenience of illustration, FIG. 5 shows a set of switching voltages 4=7x3.2t constituting one pixel
Only a is shown. Switching electric '423, 20
23. The area 5 of the PLZT substrate 22 that is clamped is a switching electrode; 23. By controlling the voltage of l with a drive circuit (not shown), it becomes a light switch region where passing light is turned on and off. E indicates the electric field generated in the optical switch region when a voltage is applied to the switching electric currents J, J. One surface of the PLZT substrate 22, the surface opposite to 22a,'! , 2b, a reflector 26 made of metal is provided. , 27 are polarizers. U is an analyzer and is arranged perpendicular to the polarizer 27. 29 is Chibanei. The polarizer 27, the analyzer 5, and the plane mirror 9 form part of the optical system. Reference numeral 30 denotes incident light emitted from, for example, a mercury lamp (not shown). 3/ is the output light controlled by the PLZT optical switching array co/ and analyzed by the analyzer 2g.

Next, the effect will be explained.

When the incident light 30 is linearly polarized in the direction of viscosity with respect to the direction of the electric field E by the polarizer 27 and reflected by the plane mirror 29, the switch region J is incident on the switch region J of the PLzT optical switching array 2/. Since the electro-optic effect caused by the electric field E causes a change in the refractive index proportional to the square of the intensity of the electric field E, the retardation wavelength, 10,000: refractive index change = η
3 B R2, η: refractive index, R1 constant, E: electric field strength,
d: PLZT substrate, effective thickness (same as the effective depth where the electric field is present) of 22 mm. This retardation r
The received light is reflected by the reflector and passes through the switch area, 25
goes in the opposite direction in the same electric field E and gets retardation r again.
In response to this, the light is emitted from the PLZT optical switching play 21, and is analyzed by a pre-analyzer arranged orthogonally to the polarizer 27 to become emitted light 3/. The intensity of the emitted light 3c, that is, the intensity of the light after passing through the analyzer d;
Since the light travels back and forth through the optical switch area j by being reflected by the reflector 26 and undergoes returnation twice, Io = II 5
in22X −= It 5in2r ・=−(II
Becomes Ko. Thus, the PLZT optical switching array 2/
a switching electrode constituting each pixel; 2. ? , 2
'/-, the voltage is turned on and off according to the information signal given in advance. In other words, the light that passes through the optical switch area 25 to which the electric field E is applied passes through the analyzer.1) The output light 3/ has a strong intensity of 1fro as shown in the equation, and the light that passes through the optical switch region 25 to which no field E is applied does not undergo retardation and the polarization state does not change. Analyzer 28
The intensity of the emitted light 3/ becomes zero. As a result,
This means that the light can be turned on and off.

In the PLZT optical switching array 2/ of this embodiment, light is reflected by the reflector rollers and reaches the optical switch area 25.
The effective thickness becomes 2d by going back and forth, and the retardation is twice that of the conventional transmission type, so the intensity of the emitted light is 3/11JI.
o becomes larger and the contrast increases.

FIG. 2 shows an application example in which the PLZT optical switching array 2/ according to the present invention is applied to an optical printer. In the figure, the light source to extending in the longitudinal direction (direction perpendicular to the plane of the paper) is a halogen lamp or a green fluorescent lamp and irradiates the sac side of the reflecting mirror through a reflecting plate 17.7.

The incident light reflected by the reflective sharp 27 passes through the polarizer 27, and then passes through the slit 3, where it forms a linear 1 (bright and 7) extending in the longitudinal direction.
Similarly, the light enters Okihi fC, PLZT optical switching array, 2/ in the longitudinal direction.

This linearly illuminated incident light is distributed in the longitudinal direction and 7t
It is controlled by each switching electrode (not shown in FIG. 6) of the PLZT optical switching array 2/. In other words, in the optical switch region between the switching electrodes to which a voltage is applied, a refractive index change proportional to the square of the electric field intensity occurs due to the electro-optic effect, and the refractive index changes in the forward path and in the return path reflected by the reflector 26, respectively. Retardation r will occur, and the output light that has passed through the analyzer U has an intensity io expressed by equation 11.In the optical switch region between the electrodes where no voltage is applied, no retardation occurs, and therefore the incident light Since the light does not undergo any change, it is blocked by the analyzer Jδ゛ arranged orthogonally to the polarizer 27, and the intensity of the emitted light becomes zero.These emitted lights are reflected by a convergent light transmitter, for example. The array Q is used to project onto the photosensitive drum.

In this optical printer, a high-contrast hard copy was obtained because the reflective PLZT optical switching array 2/ according to the present invention was used.

Note that the PLZT optical switching array according to the present invention can also be used as a spatial modulator.

As explained above, according to this invention, PbZr
PLZ' consisting of O3, PbTi o5 and La205
Several spaced apart switching electrodes were provided on one surface of the L' substrate, and a reflector was provided on the opposite surface of the L Z T substrate to form a 1PLZT optical switching array. moves back and forth within the PLZT substrate, and the effective thickness is doubled. Therefore, even if the resolution of the PLZT optical switching array is increased by reducing the interval between the switching electrodes, sufficient contrast can be obtained. That is,
The PLZT optical switching array of the present invention has the advantage of providing both high resolution and high contrast.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing a conventional PLZT optical switching array, Fig. 2 is a plan view showing another conventional PLZT optical switching array, and Fig. 3 is an example of an optical printer using a conventional PLZT optical switching array. A schematic perspective view showing,
Fig. 1 is a cross-sectional view showing a conventional PLZT optical switching array, Fig. Mj is a schematic diagram showing a section +fr of a PLZT optical switching array according to an embodiment of the present invention and a part of the optical system, and Fig. 1 is a schematic diagram showing an example of an optical printer using a PLZT optical switching play. 2/...PLZT optical switching array, Ω...P
LZT substrate 1. zz, , 24L...Switching electric hawk, 2A...Reflector. Client agent Kiyoshi Inomata (//) No.? Leap

Claims (1)

[Claims] A PLZT substrate made of Pb Zr 05, Pb Ti 05 and La2O5, a plurality of spaced apart switching electrodes provided on one surface of the PLZT substrate, and a plurality of switching electrodes provided on a surface opposite to the one surface of the PLZT substrate. 1. A PLZT optical switching array, comprising: a reflector which is a reflector;