Ceramic element, method for producing ceramic element, display device, relay device, and capacitor

Abstract

A ceramic element including a main actuator element 26 having an anti-ferroelectric film 22 and a pair of electrodes 24 a , 24 b formed on a first principal surface (front surface) of the anti-ferroelectric film 22, a vibrating section 18 for supporting the main actuator element 26, and a fixed section 20 for supporting the vibrating section 18 in a vibrating manner. The anti-ferroelectric film 22 after polarization has a region Zt in which its average dielectric constant is increased in an analog manner in accordance with a voltage V applied to the pair of electrodes 24 a , 24 b . Specifically, an expression of p/t≦2.5 is satisfied provided that an average film thickness of the anti-ferroelectric film 22 is t, and a pitch between the pair of electrodes 24 a , 24 b is p.

We claim:  
     
         1 . A method for producing a ceramic element comprising an operating section having an anti-ferroelectric film and at least a pair of electrodes formed on said anti-ferroelectric film, a vibrating section for supporting said operating section, and a fixed section for supporting said vibrating section in a vibrating manner, said method comprising the steps of: 
 stacking ceramic green sheets or ceramic green tapes followed by integrated sintering to prepare a substrate having said vibrating section and said fixed section;    forming said anti-ferroelectric film on said vibrating section of said substrate; and    sintering said anti-ferroelectric film.    
     
     
         2 . The method for producing said ceramic element according to  claim 1 , wherein said anti-ferroelectric film is subjected to a sintering treatment while applying a load.  
     
     
         3 . The method for producing said ceramic element according to  claim 2 , wherein said load is not less than 0.4 kg/cm 2 .  
     
     
         4 . The method for producing said ceramic element according to  claim 1 , wherein an anti-ferroelectric ceramic material is prepared to have a powder composition which is deviated from an optimum composition when a powder of said anti-ferroelectric ceramic material is prepared to produce said anti-ferroelectric film, while speculating variation in composition due to mutual diffusion with respect to said vibrating section during said sintering for said anti-ferroelectric film.  
     
     
         5 . The method for producing said ceramic element according to  claim 4 , wherein ZrO 2  is weighed in an amount smaller than its prescribed amount, and TiO 2  is weighed in an amount larger than its prescribed amount.  
     
     
         6 . The method for producing said ceramic element according to  claim 5 , wherein said amount of ZrO 2  is 95 to 98% provided that said prescribed amount is 100%, and/or said amount of TiO 2  is 102 to 104% provided that said prescribed amount is 100%.  
     
     
         7 . The method for producing said ceramic element according to  claim 1 , wherein when a powder of an anti-ferroelectric ceramic material is prepared to produce said anti-ferroelectric film, said powder is previously prepared in a composition in which lead oxide is contained in an amount smaller than its prescribed blending amount, and then an amount of shortage of lead component is compensated and mixed afterward in a form of lead oxide.  
     
     
         8 . The method for producing said ceramic element according to  claim 7 , wherein an amount of post-compensation for said lead component is not less than 3% and not more than 20% of said prescribed blending amount.  
     
     
         9 . The method for producing said ceramic element according to  claim 8 , wherein said amount of post-compensation for said lead component is not less than 5% and not more than 15% of said prescribed blending amount.  
     
     
         10 . The method for producing said ceramic element according to  claim 1 , wherein when a powder of an anti-ferroelectric ceramic material is prepared to produce said anti-ferroelectric film, a specific surface area of tin oxide to be used as a raw material is not less than 8 m 2 /g and not more than 20 m 2 /g.  
     
     
         11 . The method for producing said ceramic element according to claims  1 , wherein said substrate made of ceramic is produced by stacking a second layer provided with a window, a third layer to be superimposed on one side of said second layer so that said window is covered therewith, and a first layer to be superimposed on the other side of said second layer so that said window is covered therewith, said first layer having one or more through-holes at a position corresponding to said window, followed by integrated sintering.  
     
     
         12 . The method for producing said ceramic element according to  claim 1 , wherein a paste composed of a ceramic material is formed as a pattern on an upper surface of a first layer having one or more through-holes, a second layer having a window is formed at a portion corresponding to said through-holes, and then a third layer is stacked to close said window, followed by integrated sintering to produce said substrate made of ceramic.  
     
     
         13 . The method for producing said ceramic element according to  claim 11 , wherein a thickness of said second layer is 1 to 15 μm.  
     
     
         14 . A display device comprising an optical waveguide plate for introducing light thereinto, and a driving unit provided opposingly to one plate surface of said optical waveguide plate and including a number of actuator elements arranged corresponding to a large number of picture elements, for displaying, on said optical waveguide plate, a picture image corresponding to an image signal by controlling leakage light at a predetermined portion of said optical waveguide plate by controlling displacement action of each of said actuator elements in a direction to make contact or separation with respect to said optical waveguide plate in accordance with an attribute of said image signal to be inputted, wherein said actuator element comprises: 
 a main actuator element having an anti-ferroelectric film and at least a pair of electrodes formed on said anti-ferroelectric film;    a vibrating section for supporting said main actuator element; and    a fixed section for vibratingly supporting said vibrating section;    said display device further comprising a displacement-transmitting section for transmitting, to said optical waveguide plate, said displacement action of said actuator element generated by applying a voltage to said pair of electrodes.    
     
     
         15 . A capacitor comprising: 
 a vibrating section for supporting a capacitor unit; and    a fixed section for vibratingly supporting said vibrating section, wherein: 
 said capacitor unit comprises an anti-ferroelectric film formed on said vibrating section, a pair of control electrodes formed on an upper surface of said anti-ferroelectric film, and both terminal electrodes of said capacitor formed on said upper surface and a lower surface of said anti-ferroelectric film respectively.