US4119366A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mirrors with a variable focal distance
Assignee: Bpifrance Financement SA
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Filing: 1976-12-02
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Granted: 1978-10-10
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Expires: 1996-12-02
Abstract
Abstract Mirrors with a variable focal distance composed of a disc of revolution about an axis having a reflecting surface. Said disc has a variable thickness and is bent elastically by applying thereto a distributed load or an axial load and by balancing this load by a central or peripheral bearing pressure. The deformation obtained is parobolic provided that the variable thickness of the disc varies as a function of the radius from the axis. One application of the present invention is the manufacture of mirrors with a variable focal distance.
Inventors
- 👤 Gerard R. Lemaitre
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 04:42
CPC Classifications
G; G02; G02B; G02B26/00; G02B26/08; G02B26/0816; G02B26/0825
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
259 words
Mirror with a variable focal distance comprising a blank of a flexible material, of revolution about an axis, in the general form of a disc having a reflective face which has been surfaced with high precision and a rear face, opposite to said reflective face; an external radius H and a thickness h between said two faces which depends on the distance r to said axis, which disc is elastically bent by means of a variable pressure applied uniformly on one face which pressure is balanced by the reaction force of a peripheral support on which said disc bears and the reduced thickness h/H of said disc is defined at each point of said disc placed at a reduced distance ρ = r/H from said axis by the formula ##EQU14## in which E and v are respectively Young's modulus and Poisson's ratio of the material of the blank, Ω is the so-called closure coefficient of the bent mirror, p is the uniform load per unit of surface of the disc for bending said disc, and ρ = r/H is the reduced distance of the point from the axis and is included between 0 and 1, said blank comprising a crown forming one piece with the disc to which it is connected by a very thin cylindrical flange which forms said peripheral support, which crown is hermetically connected to a base so that the disc, the crown and the base form a tight enclosure, which enclosure comprises means for creating in the enclosure a variable pressure, different from ambiant pressure.
Claim 2
Dependent Claim
259 words
Mirror with a variable focal distance comprising a blank of a flexible material, of revolution about an axis, in the general form of a disc having a reflective face which has been surfaced with high precision and a rear face, opposite to said reflective face; an external radius H and a thickness h between said two faces which depends on the distance r to said axis, which disc is elastically bent by means of a variable pressure applied uniformly on one face which pressure is balanced by the reaction force of a peripheral support on which said disc bears and the reduced thickness h/H of said disc is defined at each point of said disc placed at a reduced distance ρ = r/H from said axis by the formula ##EQU14## in which E and v are respectively Young's modulus and Poisson's ratio of the material of the blank, Ω is the so-called closure coefficient of the bent mirror, p is the uniform load per unit of surface of the disc for bending said disc, and ρ = r/H is the reduced distance of the point from the axis and is included between 0 and 1, said blank comprising a crown forming one piece with the disc to which it is connected by a very thin cylindrical flange which forms said peripheral support, which crown is hermetically connected to a base so that the disc, the crown and the base form a tight enclosure, which enclosure comprises means for creating in the enclosure a variable pressure, different from ambiant pressure.
Claim 3
Dependent Claim
220 words
Mirror with a variable focal distance comprising a blank of a flexible material, of revolution about an axis, in the general form of a disc having a reflective face, which has been surfaced with high precision and a rear face, opposite to said reflective face, an external radius H and a thickness h between said two faces which depends on the distance r to said axis, which disc is elastically bent by means of an axial force of variable intensity F applied on the center of said rear face, which force is balanced by the reaction force of a peripheral support on which said disc bears and the reduced thickness h/H of said disc is defined at each point of said disc placed at a reduced distance ρ = r/H from said axis by the formula: ##EQU15## in which E and v are respectively Young's modulus and Poisson's ratio of the material of the blank, Ω is the so-called closure coefficient of the bent mirror. p= F/s is equal to the ratio between the intensity of the force F for bending said disc and the surface of said disc, ρ = r/H is the reduced distance of the point from the axis included between 0 and 1, and ln ρ 2 is the Napierian logarithm of the square reduced radius.
Claim 4
Dependent Claim
220 words
Mirror with a variable focal distance comprising a blank of a flexible material, of revolution about an axis, in the general form of a disc having a reflective face, which has been surfaced with high precision and a rear face, opposite to said reflective face, an external radius H and a thickness h between said two faces which depends on the distance r to said axis, which disc is elastically bent by means of an axial force of variable intensity F applied on the center of said rear face, which force is balanced by the reaction force of a peripheral support on which said disc bears and the reduced thickness h/H of said disc is defined at each point of said disc placed at a reduced distance ρ = r/H from said axis by the formula: ##EQU15## in which E and v are respectively Young's modulus and Poisson's ratio of the material of the blank, Ω is the so-called closure coefficient of the bent mirror. p= F/s is equal to the ratio between the intensity of the force F for bending said disc and the surface of said disc, ρ = r/H is the reduced distance of the point from the axis included between 0 and 1, and ln ρ 2 is the Napierian logarithm of the square reduced radius.
Claim 5
Dependent Claim
214 words
Mirror with a variable focal distance comprising a blank of a flexible material, of revolution about an axis, in the general form of a disc having a reflective face which has been surfaced which high precision and a rear face, opposite to said reflective face, an external radius H and a thickness h between the two faces which depends on the distance r to said axis, which disc is elastically bent by means of a variable load uniformly distributed on a face of said disc which load is balanced by the axial reaction force of a fixation secured to the center of the rear face of said disc and the reduced thickness h/H of said disc is defined in each point of said disc placed at a reduced distance ρ = r/H of said axis by the formula: ##EQU16## in which formula E and v are respectively Young's modulus and Poisson's ratio of the material of the blank, Ω is so-called closure coefficient of the bent mirror, p is the uniform load per unit of surface of the disc for bending said disc, ρ = r/H is the reduced distance of the point from the axis included between 0 and 1 and ln ρ 2 is the Napierian logarithm of the square reduced radius.
Claim 6
Dependent Claim
214 words
Mirror with a variable focal distance comprising a blank of a flexible material, of revolution about an axis, in the general form of a disc having a reflective face which has been surfaced which high precision and a rear face, opposite to said reflective face, an external radius H and a thickness h between the two faces which depends on the distance r to said axis, which disc is elastically bent by means of a variable load uniformly distributed on a face of said disc which load is balanced by the axial reaction force of a fixation secured to the center of the rear face of said disc and the reduced thickness h/H of said disc is defined in each point of said disc placed at a reduced distance ρ = r/H of said axis by the formula: ##EQU16## in which formula E and v are respectively Young's modulus and Poisson's ratio of the material of the blank, Ω is so-called closure coefficient of the bent mirror, p is the uniform load per unit of surface of the disc for bending said disc, ρ = r/H is the reduced distance of the point from the axis included between 0 and 1 and ln ρ 2 is the Napierian logarithm of the square reduced radius.
Claim 7
Dependent Claim
63 words
Mirror according to claim 2 in which said blank comprises a crown forming one piece with the disc to which it is connected by a very thin cylindrical flange which constitutes said peripheral support whose geometrical position is defined with high precision and said disc comprises means for applying a variable axial force to the center of the rear face of said disc.
Claim 8
Dependent Claim
74 words
Mirror according to claim 3 in which said disc is placed inside a casing, the edge of the disc moving freely in said casing and means being placed between the edge of said disc and the walls of said casing to form a tight fitting, and said casing comprises means for creating in said casing a variable pressure different from ambiant pressure for maintaining fixed the center of the rear face of said disc.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-10-09 | 1982-04-10 | 1982-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-10-09 | 1986-04-10 | 1986-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-10-09 | 1990-04-10 | 1990-10-10 | $7700.00 | Window Closed / Lapsed |