Bonded filter substrates

Abstract

In the examples provided herein, an apparatus has a first substrate upon which one or more first filters have been fabricated on a first surface of the first substrate. The apparatus also has a second substrate upon which one or more second filters have been fabricated on a second surface of the second substrate, wherein the one or more first filters and the one or more second filters each transmit a different band of wavelengths. Additionally, the apparatus has a bonding material that bonds the first substrate to the second substrate.

1 . An apparatus comprising:
 a first substrate upon which one or more first filters have been fabricated on a first surface of the first substrate;   a second substrate upon which one or more second filters have been fabricated on a second surface of the second substrate, wherein the one or more first filters and the one or more second filters each transmit a different band of wavelengths; and   a bonding material, wherein the bonding material bonds the first substrate to the second substrate.   
     
     
         2 . The apparatus of  claim 1 , wherein the bonding material bonds the first surface to the second surface such that the one or more first filters and the one or more second filters are positioned between the first substrate and the second substrate, and the apparatus further comprises:
 absorbing material positioned between the first substrate and the second substrate in areas not occupied by one of the filters.   
     
     
         3 . The apparatus of  claim 1 , wherein the first substrate has an opposing surface that is on an opposite side of the first substrate from the first surface, wherein the bonding material bonds the opposing surface to the second surface such that the one or more second filters are positioned between the first substrate and the second substrate, and the one or more first filters are not positioned between the first substrate and the second substrate. 
     
     
         4 . The apparatus of  claim 1 , wherein one of the first substrate and the second substrate have been ground to pre-bow the substrate. 
     
     
         5 . The apparatus of  claim 1 , further comprising a plurality of standoffs positioned between the first substrate and the second substrate to maintain a fixed separation between the first substrate and the second substrate, wherein the first surface and the second surface are coated with an anti-reflection coating, or the bonding material is index-matched to a refractive index of the first substrate and the second substrate. 
     
     
         6 . The apparatus of  claim 1 , wherein the bonding material is a two-sided sticky tape or epoxy film, or patternable material, wherein the bonding material has multiple apertures, and wherein each filter between the first substrate and the second substrate is positioned in a different one of the apertures. 
     
     
         7 .- 13 . (canceled) 
     
     
         14 . A method comprising:
 fabricating a plurality of first filters on a first surface of a first wafer, wherein the plurality of first filters each transmit a first group of wavelengths;   fabricating a plurality of second filters on a second surface of a second wafer, wherein the plurality of second filters each transmit a second group of wavelengths, and further wherein the first group of wavelengths and the second group of wavelengths are different;   determining which of the plurality of first filters and the plurality of second filters meet specifications;   dicing the first wafer to produce first sections that include one first filter that meets specifications;   bonding each of some of the first sections that include one first filter that meets specifications to one of the second sections of the second wafer that includes one second filter that meets specifications; and   dicing the second wafer to produce second sections with bonded first sections.   
     
     
         15 . The method of  claim 14 , further comprising performing one of the following: placing absorbing epoxy or index-matching material between the first sections and the second sections in areas not occupied by one of the filters; grinding the first wafer prior to dicing the first wafer; and grinding the second wafer prior to dicing the second wafer.