Method for high-speed dot array dispensing

Abstract

A dispensing apparatus and method is provided for accurately and precisely dispensing various desired patterns of reagent onto a substrate or other receptive surface or receptacle. The invention provides high-speed on-the-fly dispensing of various desired reagent patterns as provided by the operator in the form of a graphic bit map file. In one embodiment the dispensing apparatus comprises a dispensing head having an inlet end and an outlet end. The dispensing head is responsive to a first signal to dispense droplets of liquid reagent onto a substrate. The substrate or dispensing head are secured in association with a table or carriage. The table is responsive to a second signal for providing for relative X, X-Y or X-Y-Z motion between the substrate and the dispensing head. A controller is adapted to receive data representative of a desired reagent pattern and to output and coordinate the first and second signals so as to cause relative motion between the substrate and the dispensing head and, simultaneously, to cause the dispensing head to dispense droplets of liquid reagent at one or more desired locations on the substrate to form the desired reagent pattern. The controller adjusts the phase lag or lead between the first and second signals to compensate for the magnitude of relative motion between the substrate and the dispensing head given the probable trajectory of each droplet of liquid reagent. Optionally, a direct current fluid source, such as a positive displacement pump, may be provided in series with the dispensing head for precisely regulating the quantity or flow rate of liquid reagent provided to the dispensing head.

What is claimed is:  
     
         1 . A method for high-speed precision dispensing of liquid reagents onto a receptive substrate, comprising the steps of: 
 receiving data representative of a desired reagent pattern;    providing a first signal to a table or carriage to provide relative X, X-Y or X-Y-Z motion between said substrate and a dispenser;    simultaneously providing a second signal to said dispenser to cause said dispenser to dispense droplets of said liquid reagent onto said receptive substrate at predetermined locations to form said desired reagent pattern; and    adjusting the phase lag or lead between said first and second signals to compensate for the magnitude of said relative motion between said substrate and said dispenser given the probable trajectory of each said droplet.    
     
     
         2 . The method of  claim 1  comprising the step of providing said second signal to a valve to cause said valve to open and close at a predetermined frequency and duty cycle as determined by said second signal to dispense said droplets of liquid reagent.  
     
     
         3 . The method of  claim 2  comprising the step of opening and closing said valve with an electric solenoid.  
     
     
         4 . The method of  claim 2  comprising the step of adjusting the frequency and duty cycle of said valve opening and closing substantially independently of the quantity or flow rate of said liquid reagent to produce said droplets having a desired size, frequency and/or exit velocity.  
     
     
         5 . The method of  claim 1  comprising the step of receiving data in the form of a graphic bit map representative of said desired reagent pattern.  
     
     
         6 . The method of  claim 1  wherein said first and second signals comprise electrical pulses having a frequency and duration.  
     
     
         7 . The method of  claim 6  comprising the step of advancing the phase of said second signal relative to said first signal in order to compensate for the magnitude of said relative motion between said substrate and said dispenser.  
     
     
         8 . The method of  claim 6  comprising the step of advancing or retarding the phase of said first signal relative to said second signal in order to compensate for the viscosity, adhesion coefficient, temperature, pressure or density of said liquid reagent.  
     
     
         9 . The method of  claim 6  comprising the step of advancing or retarding the phase of said first signal relative to said second signal by a predetermined amount determined to reduce or minimize dispensing inaccuracies or errors for a given reagent and/or set up.  
     
     
         10 . The method of  claim 6  further comprising the step of providing a third signal to a pump device for supplying a quantity of said liquid reagent to said dispenser, said pump device being hydraulically arranged in series with said dispenser so as to regulate the amount or flow rate of said liquid reagent supplied to said dispenser.  
     
     
         11 . The method of  claim 10  further comprising the step of coordinating said second and third signals to achieve a predetermined or steady-state dispense pressure prior to dispensing operation.  
     
     
         12 . A method for dispensing desired patterns of liquid reagent onto a receptive substrate, comprising the steps of: 
 providing a first signal to a valve to cause said valve to open and close at a predetermined frequency and duty cycle as determined by said first signal to dispense droplets of said liquid reagent;    providing a second signal to a platform to provide relative X, X-Y or X-Y-Z motion between said substrate and said valve so as to cause said substrate to receive said droplets of said liquid reagent at predetermined locations; and    advancing or retarding the phase of said first signal relative to said second signal by a predetermined amount determined to reduce or minimize dispensing inaccuracies and/or to compensate for the magnitude of said relative motion between said substrate and said valve given the probable trajectory of each said droplet.    
     
     
         13 . The method of  claim 12  comprising the step of opening and closing said valve with an electric solenoid.  
     
     
         14 . The method of  claim 12  comprising the step of adjusting the frequency and duty cycle of said valve opening and closing substantially independently of the quantity or flow rate of said liquid reagent to produce said droplets having a desired size, frequency and/or exit velocity.  
     
     
         15 . The method of  claim 12  wherein said first and second signals comprise electrical pulses having a frequency and duration.  
     
     
         16 . The method of  claim 12  comprising the step of advancing the phase of said first signal relative to said second signal in order to compensate for the magnitude of said relative motion between said substrate and said valve.  
     
     
         17 . The method of  claim 12  comprising the step of advancing or retarding the phase of said first signal relative to said second signal in order to compensate for the viscosity, adhesion coefficient, temperature, pressure or density of said liquid reagent.  
     
     
         18 . A method for high-speed precision dispensing of fluids onto a target, comprising the steps of: 
 receiving data representative of a desired fluid pattern;    providing a first signal to a table or carriage to provide relative X, X-Y or X-Y-Z motion between said target and a dispenser;    simultaneously providing a second signal to said dispenser to cause said dispenser to dispense droplets of said fluid onto said target at predetermined locations to form said desired fluid pattern;    providing a third signal to a pump device for supplying a quantity of said fluid to said dispenser; and    adjusting the phase lag or lead between said first and second signals, said second and third signals and/or said first and third signals in order to provide desired offsets and/or to compensate for the magnitude of said relative motion between said substrate and said dispenser given the probable trajectory of each said droplet.    
     
     
         19 . The method of  claim 18  comprising the step of providing said second signal to a valve to cause said valve to open and close at a predetermined frequency and duty cycle as determined by said second signal to dispense said droplets of said fluid.  
     
     
         20 . The method of  claim 18  comprising the step of receiving data in the form of a graphic bit map representative of said desired fluid pattern.  
     
     
         21 . The method of  claim 18  comprising the step of advancing or retarding the phase of said first signal relative to said second signal, said first signal relative to said third signal and/or said second signal relative to said third signal in order to compensate for the viscosity, adhesion coefficient, temperature, pressure or density of said fluid.  
     
     
         22 . The method of  claim 18  comprising the step of advancing or retarding the phase of said first signal relative to said second signal, said first signal relative to said third signal and/or said second signal relative to said third signal by a predetermined amount determined to reduce or minimize dispensing inaccuracies or errors for a given fluid and/or set up.  
     
     
         23 . The method of  claim 18  further comprising the step of coordinating said second and third signals to achieve a predetermined or steady-state dispense pressure prior to dispensing operation.