Printed circuit board fluid ejection apparatus

Abstract

In an example, a method for making a fluid ejection apparatus may include forming a molding material over a fluid passage on a back surface of printhead die, embedding the printhead die in an encapsulant in a cavity in a printed circuit board such that at least one drop ejector of the printhead die is exposed at a front side of the printed circuit board, removing the encapsulant at a back side of the printed circuit board to expose the molding material, and removing the molding material to form a fluid feed slot through which fluid may flow to the fluid passage opening in the printhead die.

What is claimed is: 
     
         1 . A molded fluid ejection panel, comprising;
 at least one printhead die, each printhead die having a front surface and a back surface, the back surface comprising at least one fluid passage opening;   a printed circuit board having a cavity disposed therein; and   an encapsulant to embed the printhead die in the cavity.   
     
     
         2 . The molded fluid ejection panel of  claim 1 , wherein the cavity extends from a front side of the printed circuit board to a back side of the printed circuit board. 
     
     
         3 . The molded fluid ejection panel of  claim 1 , wherein the printhead die is a sliver die having a ratio of length to width of at least three. 
     
     
         4 . The molded fluid ejection panel of  claim 1 , wherein the printhead die is less than 500 micrometers thick. 
     
     
         5 . The molded fluid ejection panel of  claim 1 , wherein the front surface of the printhead die is exposed at a front side of the printed circuit board. 
     
     
         6 . The molded fluid ejection panel of  claim 1 , wherein the encapsulant contacts just side surfaces of the printhead die such that the front surface and the back surface are exposed. 
     
     
         7 . The molded fluid ejection panel of  claim 1 , wherein each printhead die further comprises a manifold extending lengthwise along the printhead die to deliver fluid to rows of chambers on either side of the manifold. 
     
     
         8 . The molded fluid ejection panel of  claim 1 , wherein the at least one printhead die comprises multiple printhead die arranged end to end in rows. 
     
     
         9 . The molded fluid ejection panel of  claim 8 , wherein the rows extend along a width of a substrate. 
     
     
         10 . The molded fluid ejection panel of  claim 8 , wherein printhead die in adjacent rows are staggered. 
     
     
         11 . The molded fluid ejection panel of  claim 1 , further comprising a microelectromechanical system (MEMS) device embedded in the printed circuit board. 
     
     
         12 . The molded fluid ejection panel of  claim 1 , wherein the encapsulant has a concave back surface. 
     
     
         13 . The molded fluid ejection panel of  claim 1 , wherein the printhead die is a multi-layer printhead die. 
     
     
         14 . A printhead assembly comprising:
 at least one printhead, each printhead comprising:
 multiple molded printhead die, each printhead die having a front surface and a back surface, the back surface comprising at least one fluid passage opening; 
 a printed circuit board having a cavity disposed therein; 
 an encapsulant to embed the printhead die in the cavity; and 
 an array of drop ejectors formed in the front surface of each printhead die. 
   
     
     
         15 . The printhead assembly of  claim 14 , wherein the array of drop ejectors are formed in rows on each respective printhead die. 
     
     
         16 . The printhead assembly of  claim 15 , further comprising a manifold disposed between rows of drop ejectors to deliver fluid to ejection chambers on either side of the manifold, each ejection chamber corresponding to a drop ejector of the array. 
     
     
         17 . The printhead assembly of  claim 16 , further comprising multiple passages to deliver fluid to the manifold. 
     
     
         18 . A fluid ejection system, comprising:
 a printhead assembly comprising:
 at least one printhead, each printhead comprising:
 multiple molded printhead die, each printhead die having a front surface and a back surface, the back surface comprising at least one fluid passage opening; 
 a printed circuit board having a cavity disposed therein; 
 an encapsulant to embed the printhead die in the cavity; and 
 an array of drop ejectors formed in the front surface of each printhead die; 
 
 a fluid supply assembly to supply fluid to the printhead assembly; and 
 a controller to control the printhead assembly and the fluid supply assembly. 
   
     
     
         19 . The fluid ejection system of  claim 18 , wherein the printed circuit board comprises a fluid feed slot to deliver fluid to fluid passages in the respective multiple molded printhead die. 
     
     
         20 . The fluid ejection system of  claim 18 , wherein the printed circuit board is a multi-layer printed circuit board.