JPH03215821A - Light valve electrode formation method - Google Patents

Abstract

PURPOSE:To obtain the electrode of the light valve which can suppress a driving voltage to a low level and to suppress the degradation in transmittance by pressing the (PLZT) slurry of electrooptical ceramics to form a PLZT plate, calcining this plate, and then injecting conductive pastes into the electrode holes thereof, thereby forming the electrodes. CONSTITUTION:The slurry prepd. by mixing the powder of the PLZT (Pb0.91 La0.09)(Zr0.65Ti0.35)O3), a solvent and a binder is put into metallic molds having projecting parts 10, 10, 10,... for forming the electrode holes and recesses 14, 14, 14,... for forming the electrode holes and is pressed to form the PLZT plate 20. The PLZT plate formed by the press forming is then taken out of the metallic molds 12, 16 and is calcined in a calcination furnace, by which the transparent PLZT calcined plate 32 formed with the many electrode holes 30, 30, 30,... is formed. The conductive pastes 36, 36, 36,... are then injected into the electrode holes 30, 30, 30,... by applying the conductive paste on the upper surface of this PLZT calcined plate 32 and vacuum attracting the paste from the lower part side of the PLZT calcined plate 32. Such plate is calcined, by which the electrode of the light valve is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an improvement in a method for forming electrodes of light valves used in projection displays, direct view displays, and the like.

[Conventional technology] In recent years, electro-optic ceramics P L Z T (
For example (Pbo-s1Lan-.s) (Zro-ssT
i. o. Research and development of light valves using as) Oa) has become active. Projection-type displays and direct-view displays using such light valves are expected to have high brightness and high definition, but their electrode structures have been a problem.

Conventional light valves using PLZT are made of fired PL
Electrodes have been formed by printing transparent electrodes on a ZT plate, or grooves have been formed on a fired PLZT plate using a dicing saw, and conductors have been embedded in the grooves to form electrodes. However, the method of forming electrodes by printing transparent electrodes is
Although the process is simple, since transparent electrodes are printed on the PLZT board, there are problems in that the transmittance decreases and the driving voltage increases. In addition, the method of forming electrodes by embedding a conductor in a groove can suppress the perturbation voltage to a low level, but the process of forming the groove is complicated and it is difficult to reduce the groove width, so the transmittance is There were problems in that the light was reduced and light leaked from the sides of the grooves. In order to solve these problems, the applicant has developed a method (green sheet process) in which electrodes are formed inside the PLZT sheets by laminating and firing PLZT green sheets with electrodes printed on the sheets. ) (for example, patent application 1986-10)
No. 8648).

[Problems to be Solved by the Invention] However, the electrode forming method using the previously proposed Green Sea I process is suitable for mass production and can lower the driving voltage, but the shape of the fired product is large and P
There are some problems in that the binder contained in the LZT green sheet and electrode paste can cause cracks in the fired product, and the binder remains in the fired product as residual carbon, reducing transmittance. Ta.

The present invention was made in view of the above-mentioned problems, and has a simple process, is suitable for mass production, and has low driving voltage.
Moreover, it is an object of the present invention to provide a method for forming electrodes of a light valve that can suppress a decrease in transmittance.

[Means for Solving the Problems] In the method for forming electrodes of a light valve according to the present invention, first, PLZT powder and a solvent are placed in a box-shaped lower mold having a protruding part for forming an electrode hole on the bottom surface. A PLZT slurry mixed with a small amount of binder is poured and dried. Next, an upper mold having a concave part for forming an electrode hole which can be fitted with the convex part for forming an electrode hole is inserted into the lower mold, and a PLZT plate is formed by press working. Next, this PLZT
After firing the plate, conductive paste is injected into the electrode holes to form electrodes.

[Example] Hereinafter, one embodiment of the present invention will be described based on the drawings.

(a) First, as shown in FIG. 1, a large number of convex portions 10 for forming electrode holes are formed on the bottom surface. 10, 10, . . . are provided in a protruding manner.
recesses 14, 14, 14, . . . for forming electrode holes that can be fitted with electrode holes 14, 14, 14, . . .
An upper mold 16 that can be fitted and inserted into the mold is prepared, and PLZT slurry is poured into the lower mold 12. This PLZT slurry
is PLZT (for example (Pbo.9t Lao.o9)
(Zro-6s Tj..3.)03) powder (hereinafter simply referred to as PLZT powder), a solvent, and a binder are mixed together to form a fluid. Then, leave it for a specified period of time, or
By heating, the solvent in the PLZT slurry is evaporated and dried.

(Example) After drying is completed, as shown in Fig. 2, fit the protrusions 10, 10, 10, ... for forming electrode holes into the recesses 14, 14, 14, ... for forming electrode holes. Upper mold 1
6 Fit and insert into the lower mold 12 and press PLZT.
A plate 20 is formed.

(c) Next, this press-formed P L Z T plate is taken out from the molds 12 and 16 and fired in a firing furnace, thereby forming a large number of electrode holes 30 and 3 as shown in FIG.
Transparent PLZT fired plate 3 formed with 0, 30, ...
2 is formed.

(2) Next, a conductive paste is applied to the upper surface of this PLZT fired plate 32 and vacuum suction is applied from the lower side of the PLZT fired plate 32 to form the electrode holes 30 as shown in FIG.
, 30, 30, . . . conductive paste 1-36, 36,
36, . . . are injected and fired to form the electrode of the light valve.

[Effects of the Invention] As described above, the method for forming electrodes of a light valve according to the present invention includes the steps of pouring the PLZT slurry into the lower mold and drying it, and inserting the upper mold into the lower mold and press working. DeP
Since it consists of a step of forming an LZT plate and a step of injecting a conductive paste into the electrode hole after firing the PLZT plate to form an electrode, the electrode forming process is simple and suitable for mass production. In addition, the convex part for forming electrode holes formed in the lower mold,
Since the electrode hole is formed by fitting into the recess for forming the electrode hole formed in the upper mold, it is possible to reduce the electrode width and suppress a decrease in transmittance. Also, P.L.
By pouring the ZT slurry and drying it, we fired a thin PLZT plate that did not contain conductive paste for forming electrodes, so the binder could cause cracks in the fired product during firing, or the binder could form residual carbon. It does not remain in the fired product and does not reduce transmittance. In addition, P L 7. Inject conductive paste into the electrode hole of the T-fired plate and P L Z '
Since the internal electrodes are formed within the r-plate, the driving voltage can be kept low.

[Brief explanation of drawings]

1 to 4 illustrate an example of the method for forming electrodes of a light bulb according to the present invention. FIG. 1 is a perspective view showing the upper and lower molds, and FIG. An enlarged cross-sectional view of the main parts during press processing using a mold, Fig. 3 is a perspective view showing the main parts of the PLZT fired plate, and Fig. 4 shows conductive paste injected into the electrode holes of the PLZT fired plate shown in Fig. 3. FIG. 10... Convex part for electrode hole formation, 12... Lower mold, 1
4... Concavity for electrode hole formation, 16... Upper mold, 20
...PLZT plate, 30...electrode hole, 32...PL
ZT fired plate, 36... conductive plate 71

Claims (1)

[Claims] A PLZT slurry made of a mixture of PLZT powder, a solvent, and a binder is poured into a box-shaped lower mold with a protruding part for forming electrode holes on the bottom and dried. An upper mold with a concave part for forming an electrode hole that can fit into a convex part is inserted into the lower mold and PL is performed by press working.
A method for forming an electrode for a light valve, comprising forming a ZT plate, firing the PLZT plate, and then injecting a conductive paste into the electrode hole to form an electrode.