Electrochromic display device manufacture method

Abstract

Electrochromic display device manufacture method wherein electrochromic material is deposited in a single layer on a single film of conductive material over the whole area of glass substrate and then the electrochromic material and conductive material are successively etched through a single mask which defines a display segment pattern and remains in position throughout the whole etching process, whereby etched edge portions of the different materials are in excellent alignment and there is therefore small plate area for a reverse emf cell and good display device performance is achieved. The electrochromic material may be etched by the solution employed for developing the photoresist, whereby an etching process step is eliminated.

What is claimed is: 
     
       1. An electrochromic display device .[.manufacture.]. .Iadd.manufacturing .Iaddend.method comprising the steps of: preparing a first substrate and a second substrate, at least one of said substrates being transparent;   applying a first electrode on said first substrate and a second electrode on said second substrate, at least one of said electrodes being transparent and being applied on a transparent said substrate and said second electrode serving as a counter electrode.[.;.]..Iadd., and .Iaddend.   applying a layer of transition metal oxide material on said first electrode.[.;.]..Iadd., wherein .Iaddend.   .[.initially applying.]. said first electrode and said transition metal oxide layer .Iadd.are .Iaddend.successively .Iadd.applied .Iaddend.on said first substrate over an area greater than that necessary to define a required display segment and external circuit connection pattern thereon;   forming a mask defining said required pattern on said transition metal oxide layer;   applying at least one layer of insulatory material which covers those portions of said transition metal oxide layer which are unrequired for display purposes;   successively etching said transition metal oxide layer and said first electrode through said mask .Iadd.in discrete steps and with respectively discrete etchants peculiar thereto.Iaddend., thereby producing said required pattern in said transition metal oxide layer and said first electrode;   positioning said first substrate assembly and said second substrate assembly in an electrode facing relationship and joining said assemblies by spacer means; and   introducing electrolyte into the space defined between said assemblies and said spacer means, said elecrolyte being retained in said space.   
     
     
       2. .[.Electrochromic.]. .Iadd.The electrochromic .Iaddend.display device .[.manufactured.]. .Iadd.manufacturing .Iaddend.method as claimed in claim 1, wherein said mask is a photolithographic mask constituted by a positive-type photoresist material and including the further step of developing said mask with a developer solution .Iadd.comprising a said discrete etchant for said transition metal oxide layer and .Iaddend.acting to etch said transition metal oxide layer to produce said required pattern in a single continuous process. 
     
     
       3. The method of claim 2, wherein said developer solution is alkaline. 
     
     
       4. The method of claim 3, wherein said first electrode is etched with an acid solution .Iadd.comprising a said discrete etchant therefor .Iaddend.subsequent to the etching of said transition metal oxide layer. 
     
     
       5. The method of claim 1, wherein said insulation material is placed on said transition metal oxide layer after etching of the latter to said required .[.patter.]. .Iadd.pattern .Iaddend.by: stripping said mask from said etched transition metal oxide layer and first electrode;   applying a negative photoresist material layer over said etched transition metal oxide layer and first electrode;   exposing said negative photoresist material to a light pattern corresponding to said required pattern; and   developing said exposed negative photoresist material to form said layer of insulatory material.   
     
     
       6. The method of claim 5, wherein said mask is a photolithographic mask constituted by a positive-type photoresist material and including the further step of developing said mask with a developer solution .Iadd.comprising a said discrete etchant for said transition metal oxide layer and .Iaddend.acting to etch said transition metal oxide layer to produce said required pattern in a single continuous process. 
     
     
       7. The method of claim 6, wherein said developer solution is alkaline. 
     
     
       8. The method of claim 7, wherein said first electrode is etched with an acid solution .Iadd.comprising a said discrete etchant therefor .Iaddend.subsequent to the etching of said transition metal oxide layer. .Iadd. 9. The method of claims 1, 2, 3, 4, 5, 6, 7, or 8 including the further steps of: depositing a layer of external connector material over said first electrode prior to forming said mask and outside the boundaries of said required pattern, said external connector material being etchable by the same discrete etchant as said first electrode;   wherein said mask includes a predetermined pattern for said external connector material; and   etching said layer of external connector material in said predetermined pattern through said mask, simultaneously with the etching of said first electrode. .Iaddend. .Iadd. 10. The method of claims 1, 2, 3, 4, 5, 6, 7, or 8 including the further steps of:   depositing a layer of external connector material over said first electrode prior to forming said work and outside the boundaries of said required pattern, said external connector material being etchable by the same discrete etchant as said transition metal oxide layer;   wherein said mask includes a predetermined pattern for said external connector material; and   etching said layer of external connector material in said predetermined pattern through said mask, simultaneously with the etching of said transition metal oxide layer. .Iaddend..Iadd. 11. The method of claims 1, 2, 3, 4, 5, 6, 7, or 8 wherein, subsequent to forming said required pattern in said transition metal oxide layer and prior to forming said required pattern in said first electrode, said etchant discrete to said transition metal oxide layer is removed and post baking is effected. .Iaddend..Iadd. 12. The method of claims 1, 2, 3, 4, 5, 6, 7, or 8 including the further steps of:   deposting a layer of external connector material over said first electrode prior to forming said mask and outside the boundaries of said required pattern, said external connector material being etchable by the same discrete etchant as said first electrode;   wherein said mask includes a predetermined pattern for said external connector material; and   etching said layer of external connector material in said predetermined pattern through said mask, simultaneously with the etching of said first electrode; and further,   wherein subsequent to forming said required pattern in said transition metal oxide layer and prior to forming said required pattern in said first electrode, said etchant discrete to said transition metal oxide layer is   
     
     
        removed and post baking is effected. .Iaddend..Iadd. 13.  The method of claims 1, 2, 3, 4, 5, 6, 7, or 8 including the further steps of: depositing a layer of external connector material over said first electrode prior to forming said work and outside the boundaries of said required pattern, said external connector material being etchable by the same discrete etchant as said transition metal oxide layer;   wherein said mask includes a predetermined pattern for said external connector material; and   etching said layer of external connector material in said predetermined pattern through said mask, simultaneously with the etching of said transition metal oxide layer; and further,   wherein subsequent to forming said required pattern in said transition metal oxide layer and prior to forming said required pattern in said first electrode, said etchant discrete to said transition metal oxide layer is removed and post baking is effected. .Iaddend.