High density pixel array and laser micro-milling method for fabricating array

A method for micro-milling a substrate to a predetermined depth, comprising the steps of:

• directing a laser beam at a predetermined intensity towards a first surface of a substrate of piezoelectric transducer material to be micro-milled;
• moving the substrate material relative to the laser beam at a predetermined constant velocity along a predetermined path so as to ablate a series of grooves in the surface of the substrate material by application of a predetermined uniform flux per unit area;
• the relative movement of the substrate material and laser beam along each line in said set of lines being repeated until the material has been ablated sufficiently to form a groove a predetermined depth;
• whereby grooves are ablated in a predetermined grid pattern to form a series of pixels with kerfs or grooves separating the pixels;
• and
• filling the grooves with glue material, the glue comprising a flexible epoxy material.

A method for micro-milling a substrate to a predetermined depth, comprising the steps of:

• directing a laser beam at a predetermined intensity towards a first surface of a substrate of a piezoelectric transducer material to be micro-milled;
• moving the substrate material relative to the laser beam at a predetermined constant velocity along a predetermined path so as to ablate a series of grooves in the surface of the substrate material by application of a predetermined uniform flux per unit area;
• and
• the relative movement of the substrate material and laser beam along each line in said set of lines being repeated until the material has been ablated sufficiently to form a groove of predetermined depth;
• whereby grooves are ablated in a predetermined grid pattern to form a series of pixels with kerfs or grooves separating the pixels.

A method for micro-milling a substrate to a predetermined depth, comprising the steps of:

• directing a laser beam at a predetermined intensity towards a first surface of a substrate to be micro-milled;
• moving the substrate material relative to the laser beam at a predetermined constant velocity along a predetermined path so as to ablate a series of grooves in the surface of the substrate material by application of a predetermined uniform flux per unit area;
• the relative movement of the substrate material and laser beam along each line in said set of lines being repeated until the material has been ablated sufficiently to form a groove of predetermined depth;
• whereby grooves are ablated in a predetermined grid pattern to form a series of pixels with kerfs or grooves separating the pixels;
• and
• the grid pattern comprising a circular array, with a first set of the grooves being formed in spaced, concentric, circular paths of increasing diameter, and a second set of the grooves comprise a series of spaced lines extending transversely between each adjacent pair of circular grooves.

A method of forming an ultrasonic transducer for sending and receiving ultrasonic waves, comprising the steps of:

• directing a laser beam at a predetermined intensity towards a first surface of a substrate of a piezoelectric material, the material having a second surface parallel to said first surface;
• moving the substrate material relative to the laser beam at a predetermined constant velocity along a predetermined path so as to ablate a series of grooves in the surface of the substrate material by application of a predetermined uniform flux per unit area;
• the relative movement of the substrate material and laser beam along said path being repeated for a predetermined number of passes until the material has been ablated sufficiently to form a groove of predetermined depth;
• whereby the grooves are ablated in a predetermined grid pattern to form a series of pixels with kerfs or grooves separating the pixels, each pixel having a first end at said first surface and a second end at said second surface;
• mounting an electrode at the second end of each pixel;
• connecting the electrodes to transmitter and receiver electronics;
• and
• encasing the second ends and electrodes in a layer of backing material.