1. A micro lens array comprising a plurality of convex micro lenses that are formed on a transparent substrate in an array, wherein:
the micro lenses are convex toward a surface of the substrate in a position inward of the surface of the substrate,
the top of the convex surface of the micro lenses is lower than the surface of the substrate,
the top of the convex surface of each micro lens is lower than portions of the surface of the substrate which immediately adjoin the micro lens,
a light-shielding film is formed on the surface of the substrate, and
a plating is formed on a surface of the light-shielding film, wherein the plating outwardly projects in a direction parallel to the surface of the film to be opposed to the periphery of the micro lens and to narrow the effective aperture of the micro lens.
2. A micro lens array comprising a plurality of convex micro lenses that are formed on a transparent substrate in an array, wherein:
the micro lenses are convex toward a surface of the substrate in a position inward of the surface of the substrate,
the top of the convex surface of the micro lenses is lower than the surface of the substrate,
the top of the convex surface of each micro lens is lower than portions of the surface of the substrate which immediately adjoin the micro lens,
the transparent substrate is convex in whole toward the surface of the substrate by forming a stress control film on a surface of the substrate,
the stress control film is formed as light-shielding film, and
a plating is formed on a surface of the light-shielding film, wherein the plating outwardly projects in a direction parallel to the surface of the film to be opposed to the periphery of the micro lens and to narrow the effective aperture of the micro lens.
3. An optical member comprising a micro lens array defined in claim 2 and another transparent member having a flat surface bonded to the micro lens array, wherein the surface of the substrate in which the substrate is convex and said flat surface of said another transparent member are bonded.
4. A method of producing a micro lens array defined in claim 2, the method comprising:
forming on the transparent substrate a stress control film having openings corresponding to the pattern of the micro lenses,
forming a convex resin pattern corresponding to the micro lenses in shape in positions of the transparent substrate where said openings exist, and
dry-etching the transparent substrate from the resin pattern side, thereby transferring the shape of the resin pattern and forming the micro lenses.
5. A method as defined claim 4 in which the stress control film is formed as light-shielding film by the use of a light-shielding material.
6. A method as defined claim 5 in which a plating is formed on a surface of the light-shielding film, wherein the plating outwardly projects in a direction parallel to the surface of the film to be opposed to the periphery of the micro lens and to narrow the effective aperture of the micro lens after the micro lenses are formed.
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. A method for determining a measuring point in time (tM), at which a measured value is to be produced by a field device of process automation technology, comprising the steps of:
communicating measured values of the field device at certain communication points in time (tK) via a field bus following a query from a central control unit for measured values of the field device;
approximately determining a following communication point in time (tf) from at least one time span (A) between two preceding communication points in time (tk,t\u2032k) and a preceding communication point in time (t\u2033k), which is either one of said two preceding communication points in time (tk, t\u2032k) or which is another communication point in time; and
determining the measuring point in time (tM) on the basis of said approximately determined following communication point in time (tf); wherein:
the measuring point in time (tM) should, in such case, be before the approximately determined following communication point in time (tf) and, consequently, before a reporting of the measured value such that said determined measuring point in time (tM) lies before said approximately determined following communication point in time (tf).
2. The method as claimed in claim 1, wherein:
the measurement point in time (tM) is also communicated with the measured value.
3. The method as claimed in claim 1, further comprising the step of:
calculating at least two time spans (A1, A2) between, in each case, at least two preceding communication points in time (tK1, t\u2032K1, tK2, t\u2032K2);
forming an average value (M) from the time spans (A1, A2); and
approximately determining the following communication point in time (tf) starting from the average value (M) and a preceding communication point in time (t\u2033K).
4. A field device for determining a measured point in time (tM), comprising:
a control unit;
at least one field bus communication unit, which, in the case of a query from said control unit, communicates at least one measured value; and
at least one outputcontrol unit, which controls the measuring point in time (tM) of said field device, wherein:
said at least one field bus communication unit transmits the communication point in time (tK) to said outputcontrol unit;
said outputcontrol unit approximately determines a following communication point in time (tf) from at least one time span (A) between two preceding communication points in time (tK, t\u2032K) and a preceding communication point in time (t\u2033K) which is either one of said two preceding points in time (tK, t\u2032) or which is another communication point in time; and
said outputcontrol unit determines the measuring point in time (tM) on the basis of said approximately determined following communication point in time (tf) such that said determined measuring point in time (tM) lies before the approximately determined following communication point in time (tf).