Projection lens

Claim 2

A projection lens for a cathode ray tube display consisting of three lens units, the first lens unit from the image end consisting of an element of weak optical power serving to provide correction for aperture dependent aberrations; a second lens unit providing essentially all of the positive power of the overall lens; the third lens unit consisting of a negative element having a concave image side surface and providing correction for field curvature; said second lens unit comprising of two airspaced elements and being overall biconvex, at least one of the surfaces of the elements of said second lens unit having an aspheric surface, and said facing surfaces of said elements of said second lens unit being defined on radii at the optical axis of said lens elements, which are at least twice as great as the equivalent focal length of said lens.

Claim 3

The lens of claim 1, where the first element of said second lens unit has an optical power K 2 , the second element of said second lens unit has an optical power K 3 , and 2.0>K.sub.2 /K.sub.3 >1.0.

Claim 4

The lens of claim 1, where both of the facing surfaces of said second lens unit are aspheric.

Claim 5

The lens of claim 1, where 1.3>K.sub.G2 /K.sub.0 >1.0 1.3>|K.sub.G3 /K.sub.0 |>1.0 where K G2 and K G3 are the optical powers of said second and third lens units, respectively, and K 0 is the optical power of the overall lens.

Claim 6

The lens of claim 1, where said third lens unit is optically coupled to the screen of a cathode ray tube.

Claim 7

The lens of claim 1 here said first lens unit is of negative optical power.

Claim 8

The lens of claim 1 where said first lens unit is of positive optical power.

Claim 9

The lens of claim 1 where at least one of the facing surfaces of the elements of said second lens unit has an aspheric surface.

Claim 10

The lens of claim 1 where both of the facing surfaces of the elements of said second lens unit are aspheric.

Claim 11

The lens of claim 1 wherein said lens elements may have aspheric surfaces defined by ##EQU2## where X is the surface sag at a semi-aperture distance Y from the axis A of the lens; C is the curvature of the lens surface at the optical axis A, equal to the reciprocal of the radius at the optical axis; and K is a conic constant or other surface of revolution.

Claim 12

A lens according to claim 10, as scaled to an object diagonal of approximately five inches, defined substantially as follows: ______________________________________ AXIAL DISTANCE SURFACE BETWEEN SURFACES LENS RADIUS (mm) (mm) N.sub.d V.sub.d ______________________________________ S1 115.050 L1 8.949 1.491 57.2 S2 183.743 31.946 S3 45.820 L2 21.028 1.491 57.2 S4 -525.725 13.865 S5 441.896 L3 10.922 1.491 57.2 S6 -81.690 22.318 S7 -30.780 L4 2.000 1.491 57.2 S8 Plano ______________________________________ Aspheric Surfaces: S1, S4, S5, S8 S1 S4 S5 S7 ______________________________________ D -0.614 × 0.100 × -0.275 × 10.sup.-06 -0.257 × 10.sup.-06 10.sup.-05 10.sup.-05 E 0.154 × 0.929 × -0.146 × 10.sup.-09 0.785 × 10.sup.-09 10.sup.-09 10.sup.-08 F -0.118 × -0.553 × -0.814 × 10.sup.-13 -0.149 × 10.sup.-12 10.sup.-12 10.sup.-10 G 0.264 × 0.255 × 0.655 × 10.sup.-16 0.112 × 10.sup.-16 10.sup.-15 10.sup.-13 K -- 0.010 0.010 0.010 ______________________________________ EFL = 73.24 mm Relative Aperture = 1/1.12 ______________________________________ where N d is the index of refraction of the lens elements, V d is the dispersion of the lens measured by its Abbe number, S1-S8 are successive lens surfaces, the surfaces where positive are on radii struck from the right and where negative are on radii struck from the left, and surfaces S1, S4, St, and S8 are aspheric as shown.

Claim 13

A lens according to claim 10, as scaled to an object diagonal of approximately five inches, defined substantially as follows: ______________________________________ AXIAL DISTANCE SURFACE BETWEEN SURFACES LENS RADII (mm) (mm) N.sub.d V.sub.d ______________________________________ S1 698.318 L1 5.978 1.491 57.2 S2 823.548 34.213 S3 51.553 L2 25.758 1.491 57.2 S4 -512.740 13.040 S5 311.806 L3 13.610 1.491 57.2 S6 -98.754 33.576 S7 -31.518 L4 2.000 1.491 57.2 S8 Plano ______________________________________ Aspheric Surfaces: S1, S4, S5, S6, S7 S1 S4 S5 S6 S7 ______________________________________ D -0.576 × 0.116 × 0.709 × -- -0.479 × 10.sup.-06 10.sup.-05 10.sup.-07 10.sup.-05 E 0.194 × 0.457 × 0.154 × -- 0.102 × 10.sup.-09 10.sup.-09 10.sup.-09 10.sup.-09 F -0.960 × -0.112 × -0.414 × -- -0.737 × 10.sup.-13 10.sup.-12 10.sup.-12 10.sup.-12 G 0.178 × 0.132 × 0.903 × -- -0.517 × 10.sup.-16 10.sup.-16 10.sup.-16 10.sup.-15 K 0.010 0.010 0.010 -1.000 -1.000 ______________________________________ EFL = 77.83 mm Relative Aperture = 1/1.13 ______________________________________ where N d is the index of refraction of the lens elements, V d is the dispersion of the lens measured by its Abbe number, S1-S8 are successive lens surfaces, the surfaces where positive are on radii struck from the right and where negative are on radii struck from the left, and surfaces S1, S4, S5, S6, and S7 are aspheric as shown.

Claim 14

A lens according to claim 10, as scaled to an object diagonal of approximately five inches, defined substantially as follows: ______________________________________ AXIAL DISTANCE SURFACE BETWEEN SURFACES LENS RADII (mm) (mm) N.sub.d V.sub.d ______________________________________ S1 117.348 L1 8.949 1.491 57.2 S2 222.782 41.170 S3 39.868 L2 18.411 1.491 57.2 S4 -6694.091 15.673 S5 260.930 L3 6.679 1.658 50.9 S6 -106.871 18.466 S7 -27.668 L4 2.000 1.491 57.2 S8 Plano ______________________________________ Aspheric Surfaces: S1, S4, S7 S1 S4 S7 ______________________________________ D -0.669 × 10.sup.-06 0.149 × 10.sup.-05 -0.644 × 10.sup.-05 E 0.224 × 10.sup.-09 0.145 × 10.sup.-08 0.279 × 10.sup.-07 F -0.122 × 10.sup.-12 -0.103 × 10.sup.-11 -0.591 × 10.sup.-10 G 0.221 × 10.sup.-16 0.635 × 10.sup.-15 0.509 × 10.sup.-13 K 0.010 0.010 0.010 ______________________________________ EFL = 67.85 mm Relative Aperture = 1/1.12 ______________________________________ where N d is the index of refraction of the lens elements, V d is the dispersion of the lens measured by its Abbe number, S1-S8 are successive lens surfaces, the surfaces where positive are on radii struck from the right and where negative are on radii struck from the left, and surfaces S1, S4, and S7 are aspheric as shown.

Claim 15

A lens according to claim 10, as scaled to an object diagonal of approximately five inches, defined substantially as follows: ______________________________________ AXIAL DISTANCE SURFACE BETWEEN SURFACES LENS RADII (mm) (mm) N.sub.d V.sub.d ______________________________________ S1 95.282 L1 11.210 1.491 57.2 S2 149.554 46.218 S3 53.438 L2 24.381 1.491 57.2 S4 559.853 19.172 S5 339.239 L3 9.087 1.658 50.9 S6 -124.636 29.819 S7 -38.499 L4 2.000 1.491 57.2 S8 Plano ______________________________________ Aspheric Surfaces: S1, S4, S7 S1 S4 S7 ______________________________________ D -0.190 × 10.sup.-06 0.986 × 10.sup.-06 -0.219 × 10.sup.-05 E 0.197 × 10.sup.-10 0.414 × 10.sup.-09 0.554 × 10.sup.-08 F -0.232 × 10.sup.-13 -0.206 × 10.sup.-12 -0.563 × 10.sup.-11 G 0.381 × 10.sup.-17 0.929 × 10.sup.-16 0.221 × 10.sup. -14 K 0.010 0.010 0.010 ______________________________________ EFL = 84.99 mm Relative Aperture = 1/1.10 ______________________________________ where N d is the index of refraction of the lens elements, V d is the dispersion of the lens measured by its Abbe number, S1-S8 are successive lens surfaces, the surfaces where positive are on radii struck from the right and where negative are on radii struck from the left, and surfaces S1, S4, and S7 are aspheric as shown.

Claim 16

A lens according to claim 10, as scaled to an object diagonal of approximately five inches, defined substantially as follows: ______________________________________ AXIAL DISTANCE SURFACE BETWEEN SURFACES LENS RADII (mm) (mm) N.sub.d V.sub.d ______________________________________ S1 129.775 L1 8.949 1.491 57.2 S2 250.970 31.809 S3 53.002 L2 20.260 1.491 57.2 S4 -230.155 16.007 S5 2920.596 L3 9.771 1.491 57.2 S6 -80.811 26.206 S7 -33.389 L4 2.00 1.491 57.2 S8 -600.000 ______________________________________ Aspheric Surfaces: S1, S4, S6, S7 S1 S4 S6 S7 ______________________________________ D -0.655 × 0.793 × 0.388 × -0.160 × 10.sup.-06 10.sup.-06 10.sup.-06 10.sup.-05 E 0.937 × 0.406 × 0.263 × -0.842 × 10.sup.-10 10.sup.-09 10.sup.-09 10.sup.-09 F -0.733 × -0.204 × -0.613 × 0.271 × 10.sup.-13 10.sup. -12 10.sup.-12 10.sup.-11 G 0.160 × 0.984 × 0.264 × -0.133 × 10.sup.-16 10.sup.-16 10.sup.-15 10.sup.-14 K 0.010 0.010 0.010 0.010 ______________________________________ EFL = 73.25 mm Relative Aperture = 1/1.12 ______________________________________ where N d is the index of refraction of the lens elements, V d is the dispersion of the lens measured by its Abbe number, S1-S8 are successive lens surfaces, the surfaces where positive are on radii struck from the right and where negative are on radii struck from the left, and surfaces S1, S4, S6, and S7 are aspheric as shown.

Claim 17

A lens according to claim 10, as scaled to an object diagonal of approximately five inches, defined substantially as follows: ______________________________________ AXIAL DISTANCE SURFACE BETWEEN SURFACES LENS RADIUS (mm) (mm) N.sub.d V.sub.d ______________________________________ S1 864.113 L1 6.243 1.491 57.2 S2 172.923 37.868 S3 56.297 L2 26.966 1.491 57.2 S4 -400.05 11.382 S5 187.805 L3 16.248 1.491 57.2 S6 -107.571 45.408 S7 -42.673 L4 2.000 1.491 57.2 S8 Plano ______________________________________ Aspheric Surfaces: S2, S3, S4, S6, S7 S2 S3 S4 ______________________________________ D 0.480 × 10.sup.-06 0.894 × 10.sup.-07 0.314 × 10.sup.-06 E -0.163 × 10.sup.-09 0.705 × 10.sup.-11 0.871 × 10.sup.-10 F 0.139 × 10.sup.-12 0.857 × 10.sup.-14 -0.136 × 10.sup.-12 G -0.207 × 10.sup.-16 -0.318 × 10.sup.-16 0.113 × 10.sup.-16 K 0.010 -1.000 0.01 ______________________________________ S6 S7 ______________________________________ D 0.159 × 10.sup.-06 -0.687 × 10.sup.-05 E 0.277 × 10.sup.-09 0.395 × 10.sup.-08 F -0.711 × 10.sup.-13 -0.406 × 10.sup.-11 G -0.990 × 10.sup.-17 0.638 × 10.sup.-15 K -1.000 ______________________________________ EFL = 77.744 Aperture = 1/1.13 ______________________________________ where N d is the index of refraction of the lens elements, V d is the dispersion of the lens measured by its Abbe number, S1-S8 are successive lens surfaces, the surfaces where positive are on radii struck from the right and where negative are on radii struck from the left, and surfaces S1, S4, S6, and S7 are aspheric as shown.

Claim 18

A lens according to claim 10, as scaled to an object diagonal of approximately five inches, defined substantially as follows: ______________________________________ AXIAL DISTANCE SURFACE BETWEEN SURFACES LENS RADII (mm) (mm) N.sub.d V.sub.d ______________________________________ S1 185.971 L1 8.949 1.491 57.2 S2 115.960 28.666 S3 53.594 L2 21.610 1.491 57.2 S4 -198.472 18.107 S5 180.049 L3 14.058 1.491 57.2 S6 -89.499 30.417 S7 -38.732 L4 2.000 1.491 57.2 S8 Plano ______________________________________ Aspheric Surfaces: S2, S3, S5, S7 S2 S3 S5 S7 ______________________________________ D 0.486 × -0 130 × -0.321 × -0.564 × 10.sup.-16 10.sup.-06 10.sup.-07 10.sup.-05 E -0.481 × -0.155 × -0.268 × 0.245 × 10.sup.-11 10.sup.-09 10.sup.-09 10.sup.-08 F 0.765 × -0.363 × 0.407 × -0.370 × 10.sup.-13 10.sup.-13 10.sup.-12 10.sup.-11 G -0.809 × -0.113 × -0.123 × 0.455 × 10.sup.-18 10.sup.-16 10.sup.-15 10.sup.-15 K -1.000 0.010 0.010 ______________________________________ EFL = 72.881 Relative Aperture = 1/1.12 ______________________________________ where N d is the index of refraction of the lens elements, V d is the dispersion of the lens measured by its Abbe number, S1-S8 are successive lens surfaces, the surfaces where positive are on radii struck from the right and where negative are on radii struck from the left, and surfaces S1, S4, S6 and S7 are aspheric as shown.

Claim 19

A lens according to claim 10, as scaled to an object diagonal of approximately five inches, defined substantially as follows: ______________________________________ AXIAL DISTANCE SURFACE BETWEEN SURFACES LENS RADII (mm) (mm) N.sub.d V.sub.d ______________________________________ S1 -1125.147 L1 6.243 1.491 57.2 S2 241.451 28.374 S3 57.144 L2 22.655 1.491 57.2 S4 -738.941 14.932 S5 358.660 L3 18.726 1.613 58.6 S6 -90.673 46.540 S7 -42.831 L4 2.000 1.491 57.2 S8 Plano ______________________________________ Aspheric Surfaces: S2, S3, S4, S7 S2 S3 S4 S7 ______________________________________ D 0.361 × 0.260 × 0.894 × -0.708 × 10.sup.-01 10.sup.-06 10.sup.-06 10.sup.-05 E -0.996 × 0.462 × 0.332 × 0.552 × 10.sup.-10 10.sup.-10 10.sup.-09 10.sup.-08 F 0.612 × 0.128 × 0.458 × -0.552 × 10.sup.- 10 10.sup.-12 10.sup.-13 10.sup.-11 G -0.598 × -0.685 × -0.542 × 0.136 × 10.sup.-17 10.sup.-16 10.sup.-16 10.sup.-14 K 0.010 -1.000 0.010 -1.000 ______________________________________ EFL = 77.905 Relative Aperture = 1/1.13 ______________________________________ where N d is the index of refraction of the lens elements, V d is the dispersion of the lens measured by its Abbe number, S1-S8 are successive lens surfaces, the surfaces where positive are on radii struck from the right and where negative are on radii struck from the left, and surfaces S1, S4, S6 and S7 are aspheric as shown.

Claim 20

A projection lens for a cathode ray tube display consisting of three lens units, the first lens unit from the image end consisting of an element of weak optical power providing correction for aperture dependent aberrations and having at least one aspheric surface; the second lens unit providing essentially all of the positive power of the overall lens; the third lens unit consisting of a negative element having a concave image side surface providing correction for field curvature; said second lens unit consisting of two airspaced elements and being overall biconvex at least one of the surfaces of the elements of said second group having an aspheric surface, said facing surfaces of said second lens unit being defined on radii at the optical axis of said lens elements which are at least twice as great as the equivalent focal length of said lens.

Claim 21

A projection lens for a cathode ray tube display consisting of three lens units, the first lens unit from the image end consisting of an element of weak optical power providing correction for aperture dependent aberrations and having at least one aspheric surface; the second lens unit providing essentially all of the positive power of the overall lens; the third lens unit consisting of a negative element having a concave image side surface providing correction for field curvature; said second lens unit consisting of two airspaced elements and being overall biconvex at least one of the surfaces of the elements of said second group having an aspheric surface, said facing surfaces of said second lens unit being defined on radii at the optical axis of said lens elements which are at least twice as great as the equivalent focal length of said lens.

Claim 22

The lens of claim 19, where the first element of said second lens unit has an optical power K 2 , the second element of said second lens unit has an optical power K 3 , and 2.0>K.sub.2 /K.sub.3 >1.0.

Claim 23

The lens of claim 19, where both of the facing surfaces of said second lens unit are aspheric.

Claim 24

The lens of claim 19, where 1.3>K.sub.G2 /K.sub.0 >1.0 1.3>|K.sub.G3 /K.sub.0 |>1.0 where K G2 and K G3 are the optical powers of said second and third lens units, respectively, and K 0 is the optical power of the overall lens.

Claim 25

The lens of claim 19, where said third lens unit is optically coupled to the screen of a cathode ray tube.

Claim 26

The lens of claim 19, where the element of said first lens unit is of negative optical power.

Claim 27

The lens of claim 19, where the element of said first lens unit is of positive optical power.

Claim 28

A projection lens of the type consisting of three lens units from the image end, the first lens unit consisting of an element having an aspheric surface and serving to provide correction for aperture dependent aberrations, a second lens unit of strong optical power providing substantially all of the positive optical power of said lens, and a third lens unit consisting of a negative element having a concave image side aspheric surface and providing correction for field curvature; said second lens unit consisting of two airspaced elements being overall biconvex and having at least one aspheric surface, the facing surfaces of the elements of said second lens unit being defined on radii at the optical axis of said lens which are at least twice as great as the equivalent focal length of said lens, said first and second lens units being axially spaced a distance which is a substantial percentage of the equivalent focal length of said lens.

Claim 29

A projection lens of the type consisting of three lens units from the image end, the first lens unit consisting of an element having an aspheric surface and serving to provide correction for aperture dependent aberrations, a second lens unit of strong optical power providing substantially all of the positive optical power of said lens, and a third lens unit consisting of a negative element having a concave image side aspheric surface and providing correction for field curvature; said second lens unit consisting of two airspaced elements being overall biconvex and having at least one aspheric surface, the facing surfaces of the elements of said second lens unit being defined on radii at the optical axis of said lens which are at least twice as great as the equivalent focal length of said lens, said first and second lens units being axially spaced a distance which is a substantial percentage of the equivalent focal length of said lens.

Claim 30

The lens of claim 26, where the first element of said second lens unit has an optical power K 2 , the second element of said second lens unit has an optical power K 3 , and 2.0>K.sub.2 /K.sub.3 >1.0.

Claim 31

The lens of claim 26, where both of the facing surfaces of said second lens unit are aspheric.

Claim 32

The lens of claim 26, where 1.3>K.sub.G2 /K.sub.0 >1.0 1.3>|K.sub.G3 /K.sub.0 |>1.0 where K G2 and K G3 are the optical powers of said second and third lens units, respectively, and K 0 is the optical power of the overall lens.

Claim 33

The lens of claim 26, where said third lens unit is optically coupled to the screen of a cathode ray tube.

Claim 34

The lens of claim 26, where at least one of the facing surfaces of the elements of said second lens unit are aspheric.

Claim 35

The lens of claim 26, where the element of said first lens unit is of negative optical power.

Claim 36

The lens of claim 26, where the element of said first lens unit is of positive optical power.

Claim 37

The lens of claim 26 where 1.3>K.sub.G2 /K.sub.0 >1.0 1.3>|K.sub.G3 /K.sub.0 |>1.0 where K G2 is the optical power of said second lens unit, K G3 is the optical power of said third lens unit, and K 0 is the optical power of the overall lens.

Claim 38

The lens of claim 26, where the first element of said second lens unit has an optical power K 2 , the second element of said second lens unit has an optical power K 3 , and 2.0>K.sub.2 /K.sub.3 >1.0.

Claim 39

The lens of claim 26, where both of the facing surfaces of said second lens unit are aspheric.

Claim 40

A projection lens of the type consisting of three lens units, from the image end, the first lens unit consisting of an element of weak optical power and having an aspheric surface, a second lens unit of positive optical power and a third lens unit consisting of a negative element having a concave image side aspheric surface and providing correction for field curvature; said second lens unit consisting of two airspaced elements being overall biconvex and having at least one aspheric surface, the facing surfaces of the elements of said second lens unit being defined on radii at the optical axis of said lens elements which are at least twice as great as the equivalent focal length of said lens, said first and second lens units being widely axially airspaced.

Claim 41

A projection lens of the type consisting of three lens units, from the image end, the first lens unit consisting of an element of weak optical power and having an aspheric surface, a second lens unit of positive optical power and a third lens unit consisting of a negative element having a concave image side aspheric surface and providing correction for field curvature; said second lens unit consisting of two airspaced elements being overall biconvex and having at least one aspheric surface, the facing surfaces of the elements of said second lens unit being defined on radii at the optical axis of said lens elements which are at least twice as great as the equivalent focal length of said lens, said first and second lens units being widely axially airspaced.

Claim 42

The lens of claim 37, where the first element of said second lens unit has an optical power K 2 , the second element of said second lens unit has an optical power K 3 , and 2.0>K.sub.2 /K.sub.3 >1.0.

Claim 43

The lens of claim 37, where both of the facing surfaces of said second lens unit are aspheric.

Claim 44

The lens of claim 37, where 1.3>K.sub.G2 /K.sub.0 >1.0 1.3>|K.sub.G3 /K.sub.0 |>1.0 where K G2 and K G3 are the optical powers of said second and third lens units, respectively, and K 0 is the optical power of the overall lens.

Claim 45

The lens of claim 37, where said third lens unit is optically coupled to the screen of a cathode ray tube.

Claim 46

The lens of claim 37, where at least one of the facing surfaces of the elements of said second lens unit is aspheric.

Claim 47

The lens of claim 37 where 1.3>K.sub.G2 /K.sub.0 >1.0 where K G2 is the optical power of said second lens unit, and K 0 is the optical power of the overall lens.