Projection lens apparatus

Claim 2

A projection lens apparatus provided with a projection lens system which is used for a projection display apparatus for television pictures and which comprises: a first, second and third lens, said first lens being a double-convex positive lens with one convex surface of a larger curvature facing toward a screen and having at least one aspherical surface; said second lens being a double-convex positive lens and having one convex surface of a larger curvature facing toward said screen and disposed behind said first lens; and said third lens being a negative lens having one concave surface of a larger curvature facing toward said screen, and having a bi-aspherical surface and being disposed behind said second lens, said first, second and third lenses being arranged in the order from the screen side, said first lens being a plastic lens, said second lens being a glass lens, and said third lens being a plastic lens, said projection lens apparatus satisfying the following conditions: (1) 0.4|γ 4 |<γ 3 <0.75|γ 4 (2) 0.5<f/f 1 <0.8 (3) 0.8<f/f 2 <1.0 (4) -1.2<f/f 3 <-0.9 (5) 1.3<f 1 /f 2 <1.8 (6) 0.35f<d4<0.55f and (7) 4γ 1 <|γ 2 | where f: the focal length of said projection lens system, f 1 : the focal length of said first lens, f 2 : the focal length of said second lens, f 3 : the focal length of said third lens, d 4 : the distance between said second lens and said third lens, γ 1 : the radius of curvature of the surface at the screen side, i.e., the front surface, of said first lens, γ 2 : the radius of curvature of the rear surface of said first lens, γ 3 : the radius of curvature of the front surface of said second lens, and γ 4 : the radius of curvature of the rear surface of said second lens.

Claim 3

A projection lens apparatus according to claim 1, having f of 140.02 mm, an aperture ratio of f/1.01, a half view angle of 23.3° and the following dimensions: ______________________________________ R D N ν ______________________________________ 147.505*.sup.1 22.83 1.491 57.2 L.sub.1 -768.890 103.40 149.949 23.06 1.589 61.0 L.sub.2 -224.496 60.42 -68.655*.sup.2 6.90 1.491 57.2 L.sub.3 -3379.868*.sup.3 ______________________________________ where R: a radius of curvature, D: a distance between the surfaces, N: an index of refraction, ν: Abbe number, and *: an aspherical surface, the symbol * being given by the following equation: ##EQU7## where x is an amount of deviation from the vertex of the lens at a position spaced by the semi-aperture distance from the optical axis of lens, AD, AE, AF and AG are aspherical coefficients and K is a conic constant, the aspherical coefficients and the conic constant being as follows: ______________________________________ *1 *2 *3 ______________________________________ AD: -1.1823 × 10.sup.-7 -1.6693 × 10.sup.-11 1.8603 × 10.sup.-6 AE: 9.1990 × 10.sup.-12 2.8769 × 10.sup.-14 -1.0821 × 10.sup.-9 AF: -3.3846 × 10.sup.-15 4.6312 × 10.sup.-18 2.6821 × 10.sup.-13 AG: 2.6734 × 10.sup.-19 4.0000 × 10.sup.-18 -2.6000 × 10.sup.-17 K: 1.5934 × 10.sup.-1 -6.3300 × 10.sup.-5 2.4520 × 10.sup.3 ______________________________________

Claim 4

A projection lens apparatus according to claim 1, having f of 116.89 mm, aperture ratio f/1.07, a half view angle of 23.3° and the following dimensions: ______________________________________ R D N ν ______________________________________ 97.656*.sup.1 19.39 1.491 57.2 L.sub.1 -4804.913*.sup.2 86.02 115.067 14.39 1.589 61.0 L.sub.2 -273.293 49.15 -55.849*.sup.3 4.00 1.491 57.2 L.sub.3 507.712*.sup.4 ______________________________________ Where R: a radius of curvature, D: a distance between the surfaces, N: an index of refraction, and ν: Abbe number, the symbol * designating an aspherical surface given by ##EQU8## where x is an amount of the deviation from the vertex of lens at the position spaced by the semi-aperture distance from the optical axis of lens, AD, AE, AF and AG are aspherical coefficients and K is a conic constant, the aspherical coefficients and the conic constant being as follows: __________________________________________________________________________ *1 *2 *3 *4 __________________________________________________________________________ AD: -1.6326 × 10.sup.-7 -5.4613 × 10.sup.-8 -3.7667 × 10.sup.-7 -1.1130 × 10.sup.-7 AE: -1.3586 × 10.sup.-11 1.4308 × 10.sup.-11 2.2573 × 10.sup.-10 -4.0357 × 10.sup.-11 AF: -7.7066 × 10.sup.-15 -5.8274 × 10.sup.-15 8.3169 × 10.sup.-14 2.3370 × 10.sup.-14 AG: 1.3647 × 10.sup.-18 9.3074 × 10.sup.-19 1.7814 × 10.sup.-17 -3.4620 × 10.sup.-19 K: 0 0 0 0 __________________________________________________________________________

Claim 5

A projection lens apparatus according to claim 1, having f of 117.55 mm, aperture ratio of f/1.07 and a half view angle of 23.3° and the following dimensions: ______________________________________ R D N ν ______________________________________ 98.310*.sup.1 19.85 1.491 57.2 L.sub.1 21997.6*.sup.2 83.08 113.758 14.39 1.589 61.0 L.sub.2 -245.108 48.41 -55.356*.sup.3 3.90 1.491 57.2 L.sub.3 830.755*.sup.4, ______________________________________ where R is a radius of curvature, D a distance between the surfaces, N an index of refraction, and ν Abbe number, the symbol * designating an aspherical surface given by ##EQU9## where x is an amount of deviation from the vertex of the lens, at the position spaced by the semi-aperture distance Y from the optical axis, AD, AE, AF and AG are aspherical coefficients and K is a conic constant, __________________________________________________________________________ *1 *2 *3 *4 __________________________________________________________________________ AD: -1.6706 × 10.sup.-7 -5.8324 × 10.sup.-8 -7.4476 × 10.sup.-7 -1.2650 × 10.sup.-7 AE: -1.4185 × 10.sup.-11 1.4525 × 10.sup.-11 3.3530 × 10.sup.-10 -3.9947 × 10.sup.-11 AF: -8.1843 × 10.sup.-15 -5.7270 × 10.sup.-15 1.0335 × 10.sup.-13 2.3473 × 10.sup.-14 AG: 1.3520 × 10.sup.-18 8.1474 × 10.sup.-19 1.5508 × 10.sup.-17 -1.1189 × 10.sup.-18 K: -2.5983 × 10.sup.-2 1.7931 × 10.sup.3 2.1057 × 10.sup.-2 -5.3698 × 10 __________________________________________________________________________

Claim 6

A projection lens apparatus according to claim 1, having f of 114.85 mm, aperture ratio of f/1.09, and a half view angle of 23.3° and the following dimensions: ______________________________________ R D N ν ______________________________________ 118.573*.sup.1 16.40 1.491 57.2 L.sub.1 -1464.500 78.22 131.594 15.77 1.589 61.0 L.sub.2 -189.998 58.88 -55.092*.sup.2 4.00 1.491 57.2 L.sub.3 539.375*.sup.3 ______________________________________ where R is a radius of curvature, D a distance between the surfaces, N an index of refraction, and ν Abbe number, the symbol * designating an aspherical surface given by ##EQU10## where x is an amount of deviation from the vertex of the lens opening and at position spaced by the semi-aperture distance from the optical axis, AD, AE, AF and AG are aspherical coefficients respectively and K is a conic constant, the aspherical coefficients and the conic constant being as follows: ______________________________________ *1 *2 *3 ______________________________________ AD: -1.8904 × 10.sup.-7 -3.6405 × 10.sup.-7 0 AE: 1.5789 × 10.sup.-12 -4.3471 × 10.sup.-10 0 AF: -5.8118 × 10.sup.-15 3.4239 × 10.sup.-13 -7.3540 × 10.sup.-14 AG: 2.9601 × 10.sup.-19 -1.1332 × 10.sup.-17 2.0291 × 10.sup.-17 K: 0 0 0 ______________________________________

Claim 7

A projection lens apparatus according to claim 1, having f of 115.50 mm, an aperture ratio of f/1.09, and a half view angle of 23.3°, and the following dimensions: ______________________________________ R D N ν ______________________________________ 116.822*.sup.1 15.00 1.491 57.2 L.sub.1 -2690.000 79.80 121.536 16.50 1.589 61.0 L.sub.2 -188.770 55.30 -54.228*.sup.2 4.00 1.491 57.2 L.sub.3 551.979*.sup.3, ______________________________________ where R is a radius of curvature, D a distance between the surfaces, N an index of refraction, and ν Abbe number, the symbol * representing an aspherical surface given by ##EQU11## where x is an amount of deviation from the vertex of the lens and at the position spaced by the semi-aperture distance Y opening from the optical axis, AD, AE, AF and AG are aspherical coefficients and K is a conic constant, the aspherical coefficients and the conic constant being as follows: ______________________________________ *1 *2 *3 ______________________________________ AD: -1.8173 × 10.sup.-7 -8.1474 × 10.sup.-7 0 AE: -1.3921 × 10.sup.-12 3.4278 × 10.sup.-10 0 AF: -7.7772 × 10.sup.-15 -2.2008 × 10.sup.-13 -8.6139 × 10.sup.-14 AG: 6.5049 × 10.sup.-19 1.4414 × 10.sup.-16 2.6743 × 10.sup.-17 K: 0 0 0 ______________________________________

Claim 8

A projection lens apparatus according to claim 1, wherein one component comprises a glass face plate of the cathode-ray tube which emits pictures to be enlarged and projected by said projection lens system, the surface of said glass face plate being shaped as a plano-convex lens having the convex surface of larger curvature being the fluorescent side.

Claim 9

A projection lens apparatus according to claim 7, which satisfies the following condition: 0.15P<f/|r.sub.f |<P, where P: Petzval sum of said projection lens system, f: focal length of the projection lens system, and r f : radius of curvature of surface of said glass face plate of said cathode-ray tube on the fluorescent side.

Claim 10

A projection lens apparatus according to claim 7, having f of 96.92 mm, an aperture ratio of f/0.89, and a half view angle of 27.0° and the following dimensions: ______________________________________ R D N ν ______________________________________ 81.266*.sup.1 24.00 1.491 57.2 L.sub.1 8041.5*.sup.2 56.21 107.784 17.19 1.589 61.0 L.sub.2 -162.452 38.46 -66.324*.sup.3 4.00 1.491 57.2 L.sub.3 192.269*.sup.4 7.02 ∞ 11.30 1.507 57.5 FP -2350.0 ______________________________________ where FP designates the face place glass of said cathode-ray tube spaced 7.02 mm from said third lens L3 which is plan-convex-lens-like shaped and has a radius of curvature of -2350.0 at the rear surface (at the fluorescent side), R a radius of curvature, D a distance between the surfaces, N an index of refraction, ν Abbe number, and * an aspherical surface given by ##EQU12## where x is an amount of deviation from the vertex of the lens and at the position spaced by the semi-aperture distance Y from the optical axis, AD, AE, AF and AG are aspherical coefficients and K is a conic constant, AD, AE, AF, AG and K being as follows: __________________________________________________________________________ *1 *2 *3 *4 __________________________________________________________________________ AD: -2.76622 × 10.sup.-7 9.12985 × 10.sup.-8 -6.41927 × 10.sup.-6 -2.36123 × 10.sup.-6 AE: -1.52745 × 10.sup.-11 -1.04358 × 10.sup.-11 3.34918 × 10.sup.-9 4.83295 × 10.sup.-10 AF: -1.90966 × 10.sup.-14 -1.53427 × 10.sup.-14 -5.65787 × 10.sup.-13 1.30169 × 10.sup.-13 AG: -1.06965 × 10.sup.-19 2.94458 × 10.sup.-18 1.65240 × 10.sup.-17 -4.39349 × 10.sup.-17 K: 0 0 0 0 __________________________________________________________________________