1. A liquid ejection head comprising:
a liquid-ejection-head substrate having a surface on which energy-generating elements that generate energy to be used in ejecting liquid are provided;
a member having an opposing portion and a plurality of through holes extending through the opposing portion, the opposing portion facing the surface of the liquid-ejection-head substrate, wherein some of the through holes functioning as ejection ports are provided in correspondence with the energy-generating elements and through which the liquid is ejected; and
a light-receiving element provided on the surface of the liquid-ejection-head substrate to face at least one of the through holes, the light-receiving element outputting a current having a level that changes according to the intensity of light applied thereto.
2. The liquid ejection head according to claim 1, wherein the member is made of cured epoxy resin.
3. The liquid ejection head according to claim 1, wherein the plurality of through holes are produced by making a first opening and a second opening communicate with each other, the first opening being provided in a first surface of the member that faces the surface of the liquid-ejection-head substrate, the second opening being provided in a second surface of the member opposite the first surface.
4. The liquid ejection head according to claim 1, wherein the plurality of through holes are produced at a time by performing exposure and development on a photosensitive resin material.
5. The liquid ejection head according to claim 1, wherein the light-receiving element extends over an area including areas of the surface of the liquid-ejection-head substrate defined by projections of the through holes.
6. The liquid ejection head according to claim 1, wherein the member has a transmittance of 5% to 95% on a perimeter of each of the through holes exposed to light having a wavelength ranging from 220 nm to 360 nm.
7. The liquid ejection head according to claim 1, wherein the light-receiving element includes a plurality of wires made of a material whose resistance changes when light is applied thereto.
8. The liquid ejection head according to claim 7, wherein the material is any of a compound semiconductor, an amorphous semiconductor, and a polycrystalline semiconductor.
9. The liquid ejection head according to claim 1, wherein the light-receiving element comprises a semiconductor device that stores charge by receiving light.
10. The liquid ejection head according to claim 9, wherein the light-receiving element comprises a charge-coupled device or a complementary-metal-oxide-semiconductor device.
11. A liquid ejection apparatus to which the liquid ejection head according to claim 1 is attachable, the apparatus comprising a unit configured to apply light to the liquid ejection head from above the member.
12. A method of inspecting the liquid ejection head according to claim 1, comprising:
applying light to the light-receiving element through the through hole; and
measuring the level of current that is output from the light-receiving element.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An MRAM reference cell sub-array programming apparatus comprising:
a fixture for retaining a substrate onto which a substrate comprising a plurality of MRAM reference cell sub-arrays in communication with a plurality of sense amplifiers formed on said substrate, said plurality of MRAM reference cell sub-arrays comprising:
a plurality of MRAM cells arranged in rows and columns;
a plurality of bit lines, each bit line associated with a free magnetic layer of each MRAM cell of a column of the plurality of MRAM cells, and
a coupling to connect the bit lines of pairs of the columns of the plurality of MRAM cells together;
a control apparatus in communication with said plurality of MRAM reference cell sub-arrays for isolating said plurality of MRAM reference cell sub-arrays from said plurality of sense amplifiers;
a magnetic field generation device placed in near proximity to generate a magnetic field having an orientation to a desired magnetic orientation of said plurality MRAM cells; and
a free layer programming device for conveying a free layer programming current in a first direction on each bit lines of the first column of the pairs of columns of MRAM cells to be transferred through said coupling to each bit line of the second column of the pairs of columns of MRAM cells;
wherein a pair of the MRAM cells of said pair of columns are on a common row of said MRAM cells and a first of said pair of MRAM cells is programmed to a first magneto-resistive state and a second of said pair of MRAM cells is programmed to a second magneto-resistive state such that when one row of MRAM cells are selected for read, said pair of MRAM cells are placed in parallel to generate said mid-point reference current.
2. The MRAM reference cell sub-array programming apparatus of claim 1 further comprising:
a write word line current generator for conveying a write word line current generator in a second direction on selected word lines associated with rows of said MRAM cells.
3. The MRAM reference cell sub-array programming apparatus of claim 1 wherein at the completion of the programming of each of the plurality of MRAM reference cell sub-arrays, the free layer programming device terminates the free layer programming current and the control device reconnects each of the plurality sense amplifiers to communicate with each its associated column of plurality of MRAM reference cell sub-arrays.
4. The MRAM reference cell sub-array programming apparatus of claim 2 wherein at the completion of the programming of each of the plurality of MRAM reference cell sub-arrays, the free layer programming device terminates the free layer programming current, the write word line current generator terminates the write word line current, and the control device reconnects each of the plurality sense amplifiers to communicate with each its associated column of plurality of MRAM reference cell sub-arrays.
5. A method for programming reference MRAM cells within a sub-array of rows and columns of MRAM cells, comprising the steps of:
providing a substrate;
forming a plurality of MRAM reference cell sub-arrays in communication with a plurality of sense amplifiers formed on said substrate, said forming the plurality of MRAM reference cell sub-arrays comprising the steps of:
forming a plurality of MRAM cells to be arranged in rows and columns;
forming a plurality of bit lines such that each bit line is associated with a free magnetic layer of each MRAM cell of a column of the plurality of MRAM cells, and
forming a coupling to connect the bit lines of pairs of the columns of the plurality of MRAM cells together;
retaining said substrate on a fixture;
isolating selected columns of MRAM cells from associated sense amplifiers;
selecting a pair of the MRAM cells on one pair of columns on a common row of said MRAM cells;
programming a first of said pair of MRAM cells to a first magneto-resistive state and a second of said pair of MRAM cells to a second magneto-resistive state;
reading one row of MRAM cells by placing said pair of MRAM cells in parallel to generate said mid-point reference current;
wherein programming the first of said pair and the second of said pair of MRAM cells comprises the steps of:
generating a magnetic field having a desired magnetic orientation to program free magnetic layers of said selected pair of the MRAM cells,
placing said magnetic field in near proximity to said substrate to program selected pair of the MRAM cells, and
conveying a free layer programming current on each bit line of said selected pair of the MRAM cells to program the free magnetic layers of said selected MRAM cells.
6. The method for programming reference MRAM cells of claim 5 further comprising the step of:
conveying a write word line programming current on each word line associated with a row of said selected pair of the MRAM cells to program the free magnetic layers of said selected pair of the MRAM cells.
7. The method for programming reference MRAM cells of claim 5 further comprising the step of:
at the completion of the programming of each of said selected pair of the MRAM cells, terminating the free layer programming current; and
reconnecting each of the plurality sense amplifiers to communicate with each bit line of each column of said selected pair of the MRAM cells.
8. The method for programming reference MRAM cells of claim 6 further comprising the step of:
at the completion of the programming of each of said selected pair of the MRAM cells, terminating the free layer programming current;
terminating said write word line programming current; and
reconnecting each of the plurality sense amplifiers to communicate with each bit line of each column of said selected pair of the MRAM cells.