DE1472135C - Lens for recording and projection - Google Patents

Description

The invention relates to a lens for recording and projection, which consists of a meniscus-shaped negative individual front lens and from a modified Gaussian type, which is arranged at a great distance established positive basic system, with this basic system six standing in the air Individual lenses, namely two negative and four positive lenses, the two negative lenses the diaphragm include, two positive lenses are arranged in front of or behind these negative lenses and wherein the two lenses closest to the diaphragm in the direction of light than concave against this diaphragm Menisci are formed, while the remaining four lenses of the basic system consist of bi-lenses. There are wide-angle lenses with a long focal length known in which a far ahead negative meniscus is followed by a positive basic system based on a modified Gaussian type. This However, objectives either have a relatively small relative aperture or they require to Achieving larger relative openings a high number of lenses or the optical correction shows disturbing Residual errors.

Furthermore, lenses are known that only as

modified Gaussian lenses are built and not a common one with a preceding negative image form optical system. With these lenses a high relative aperture can be achieved, but then the angle of view and back focus are clearly limited.

Such a well-known lens has the high relative aperture of 1: 1.6, but it only draws a ' Angle of view of 2 σ <. 25 ° with a back focus of s' <0.6 / off. Therefore, this lens can never can be used where, in addition to high light intensity, there is also a large angle of view and a large focal length are required, especially with the smaller focal lengths of the lens series is the case for cinema and television technology.

The object of the invention is to achieve the advantageous properties of the two basic types mentioned to use at the same time and with the least possible optical effort a lens with a relative Opening of at least 1: 2 with an angle of view of 2> 50 ° and a long back focus s'> 0.8 / with high demands on the overall correction create.

According to the invention, this task becomes unusual in a lens for recording and projection extensive stretching of the transverse coma solved that for. the partial focal lengths, radii and airspaces the following relations are fulfilled:

0.95 / <f _B <1.05 /

1.8 / <\ f _A \ ~ fc < 2.2 /

1.5 r ₃ <| r ₄ | <3 r ₃

1.5 r ₆ < T ₁ < 3 r ₆

1.5 r ₁₀ <r _n <3 r ₁₀

0.03 / </ ₃ <0.06 /

0.01 f <I ₅ < 0.03 /

In this table and in the following example -

/ = Total focal length of the lens. f _A = focal length of the negative meniscus. f _B = focal length of the positive basic system. ~ f _c = focal length of the one in front of the aperture

Part of the lens, r = radii.
/ = Air spaces.

2 σ = total angle of view of a lens. s' = back focus (distance from the last lens vertex to the image plane). n _d = refractive index of an optical medium

for light with a wavelength of 587.6 nm.. v _d = Abbe number.

In claim 2 and in the drawing is an example specified for a lens corresponding to the invention.

1 sheet of drawings

Claims (2)

Patent claims: 1. Bright lens for recording and projection according to inverse teletype with an image angle 2σ > 50 °, a focal length 's' ^ 0.8 /, consisting of a meniscus-shaped, negative individual front lens and a downstream lens at a great distance from this front lens Six positive basic system built up in the air according to a modified Gaussian type, this basic system being formed from two negative and four positive lenses, of which the two negative lenses enclose the diaphragm and two positive lenses are arranged in front of and behind these negative lenses and the two in The light direction closest in front of the diaphragm lenses are designed as menisci concave towards this diaphragm, while the remaining four lenses of the basic system are bi-lenses, characterized in that the following relationships are fulfilled for the partial focal lengths, radii and air spaces: 0.95 / < Sb < 1.05 / 1.8 / <SaW Sc < 2.2 / 1.5 r ₃ <kl <3 r ₃ 1.5 r ₆ < r ₇ <* " % r 1.5 ho <r _n <3 T ₁ 0.03 / < / 3 <0.06 / 0.01 / < I ₅ <0.03 / 2. Lens according to claim 1, characterized by the values listed in the following table: / = 100, s' = 82.88, relative opening 1: 2, 2 σ = 51 ^c h = + 152.43 _; di = 7.34 1 J n _d 4th n _d 5 = 1.6056 r ₂ - + 67.8 k = 49.57 n _dl r ₃ = + 110.21 d ₂ = 18.36 6th = 1.6667 r ₄ = -246.76 I ₂ = 0.31 n _d n _dl r ₅ = + 50.16 d ₃ = 13.46 = 1.6636 r ₆ = + 105.71 H = 5.51 ri = + 196.55 d ₄ = 4.28 = 1.6072 r ₈ = + 39.78 11.60 '4 ~ 7.68 r _g = -67.80 d ₅ = 3.67 = 1.7174 ho = + 133.04- I ₅ = 1.35 hi = + 386.17 d ₆ = 15.30 = 1.6636 hl = -70.59 ' H = 0.31 r _l3 = + 125.02 d ₇ = 13.46 = 1.6204 ^r 14 = -122.58 =. 43.9 v ₂ = 48.4 v ₃ = 56.4 ■ v ₄ = 40.2 = 29.5 v ₆ = 56.4 ν _Ί = 60.3