Automatic visibility correction viewfinder system for optical devices

Claim 2

A viewfinder system having a viewfinder with a first optical system (12), including an adjustable lens (10), said viewfinder system comprising: an eye refractometer means (14,74) having a second optical system for detecting the eye refractive power of an eye of a person viewing into the viewfinder and generating an output whose value is related to the magnitude of said refractive power; and a visibility correction means (70,26,28), responsive to said output, for adjusting a position of said adjustable lens (10) of said first optical system (12) in accordance with the value of said refractive power to thereby correct the visibility of said viewfinder for the vision of the viewer.

Claim 3

The viewfinder system of claim l wherein said eye refractometer means (14,74) further comprises: a source (30,80) of a reference image (P1,P1ʹ) an image sensor means (64) for detecting images projected thereon; a light transmission means (16,76) comprising a third optical system (32,82), optically coincident with at least a part of said first optical system (12), for receiving said reference image (P1,P1ʹ) at a first end thereof and projecting it from a second end thereof onto the retina of a viewers eye; and a light reception means (18,78) comprising a fourth optical system (46,84), optically coincident with at least a part of said first optical system (12) for receiving the reflection of said reference image from the retina at a first end thereof and projecting it from a second end thereof onto said image sensor means (64).

Claim 4

The viewfinder system of claim 2 wherein said light reception means (48,84) further comprises means responsive to the movement of said reference image on the retina of the viewers eye as a function of the refractive power of the eye to produce two images (P4,P5;P4ʹ,P5ʹ) at said second end thereof which are projected onto said image sensor means (64) with a displacement therebetween representative of the magnitude of said eye refractive power.

Claim 5

The viewfinder system of claim 2 wherein said light transmission means (16,76) further comprises a first mask means (42,88) disposed in said third optical system (32,82) for shaping said reference image and said light reception means (18,78) further comprises a second mask means (58,92) disposed in said fourth optical system (46,84) for shaping said reflected reference image.

Claim 6

The viewfinder system of claim 4 wherein said first mask means (42,88) and said second mask means (58,92) are integrally formed into a single mask structure.

Claim 7

The viewfinder system of claim 2 wherein said third optical system (32,82) and said fourth optical system (46,84) are optically coincident with each other in a first part, said first part further including that portion of the two systems that are optically coincident with said part of said first optical system (12).

Claim 8

The viewfinder system of claim 6 wherein said first part extends prior to a point substantially conjugate with pupil when viewed from said first end of said light transmission means.

Claim 9

The viewfinder system of claim 6 wherein said common optical part includes a reduction lens (96) that is aspheric.

Claim 10

The viewfinder system of claim 1 wherein said visibility correction means (70,26,28) further comprises a calculation means (70), using a predetermined calculation, for generating a lens position correction signal in response to an output from said image sensor means (64).

Claim 11

The viewfinder system of claim 1 wherein said visibility correction means (70,26,28) further comprises a conversion table means for generating a lens position correction signal in response to the output from said image sensor means (64).

Claim 12

The viewfinder system of claim 1 wherein said system output is applied to an optomiter.

Claim 13

The viewfinder system of claim 2 wherein said reference image, when projected from said second second end of said light transmission means (16,76) may be simultaneously observed in two different directions through two peripheral points on the viewers eye so that two refocused images can be obtained.

Claim 14

The viewfinder system of claim 12 wherein said two refocused images are passed by said light reception means (18,78) onto said image sensor means (64).

Claim 15

A veiwfinder system comprising: a first optical system (12) having an adjustable lens (10); and an eye refractometer means (14,74) having a second optical system for detecting the eye refractive power of an eye of a person viewing into the viewfinder and generating an output whose value is related to the magnitude of said refractive power, said second optical system having a partially common optical axis with said first optical system (12).

Claim 16

A veiwfinder system comprising: a first optical system (12) having an adjustable lens (10); and an eye refractometer means (14,74) having a second optical system for detecting the eye refractive power of an eye of a person viewing into the viewfinder and generating an output whose value is related to the magnitude of said refractive power, said second optical system having a partially common optical axis with said first optical system (12).

Claim 17

The viewfinder system further comprising: a visibility correction means (70,26,28), responsive to said output, for adjusting a position of said adjustable lens (10).

Claim 18

The viewfinder system further comprising: a visibility correction means (70,26,28), responsive to said output, for adjusting a position of said adjustable lens (10).

Claim 19

A viewfinder system having a viewfinder with an optical system (12), including an ajustable lens (10), said viewfinder system comprising: an eye refractometer means (14,74) for detecting the eye refractive power of an eye of a person viewing into the viewfinder and generating an output whose value is related to the magnitude of said refractive power; said eye refractometer means (14,74) including: a light transmission system (32,82) having a first point substantially conjugate with a retina of the eye and located at a terminal end of an optical path of said light transmission system (32,82), a second point substantially conjugate with the retina and different from said first point and located on the midway of the optical path of said transmission system (32,82), and a third point substantially conjugate with a pupil of the eye; a light reception system (46,84) having another first point substantially conjugate with the retina and located at a terminal end of an optical path of said light reception system (46,84), another second point substantially conjugate with the retina and different from said other first point and located on the midway of the optical path of said light reception system (46,84), and another third point substantially conjugate with the pupil of the eye; a light source (30,80) disposed at the terminal end of said light transmission system (32,82); a linear positional detector means (64) disposed in said light reception system (46,84), a visibility correction means (70,26,28), responsive to an output, from said linear positional detector means (64) for adjusting a position of said adjustable lens (10) of said optical system (12) of said viewfinder; reflection means (36,38,48,36A,38A) for partially commonly arranging the optical axes of said eye refractometer means (14,74) and said viewfinder; a first mask (42,88) disposed in conjugate relation with the pupil in said light transmission system (32,82) and having an opening (40;40A) around the optical axis thereof; a second mask (58,92) disposed in conjugate relation with the pupil in said light reception system (46,84) and having a pair of openings (54,56;54A,56A) in symmetrical relation with each other with respect to the optical axis thereof; wherein the respective openings (40,40A;54,54A;56,56A) of said light transmission system (32,82) and said light reception system (46,84) are arranged so as to allow luminous flux to pass therethrough without any overlapping; and said light reception system (46,84) includes a pair of symmetrical optical sub-systems disposed between said second mask (58,92) and said light source (30,80).

Claim 20

A viewfinder system having a viewfinder with an optical system (12), including an ajustable lens (10), said viewfinder system comprising: an eye refractometer means (14,74) for detecting the eye refractive power of an eye of a person viewing into the viewfinder and generating an output whose value is related to the magnitude of said refractive power; said eye refractometer means (14,74) including: a light transmission system (32,82) having a first point substantially conjugate with a retina of the eye and located at a terminal end of an optical path of said light transmission system (32,82), a second point substantially conjugate with the retina and different from said first point and located on the midway of the optical path of said transmission system (32,82), and a third point substantially conjugate with a pupil of the eye; a light reception system (46,84) having another first point substantially conjugate with the retina and located at a terminal end of an optical path of said light reception system (46,84), another second point substantially conjugate with the retina and different from said other first point and located on the midway of the optical path of said light reception system (46,84), and another third point substantially conjugate with the pupil of the eye; a light source (30,80) disposed at the terminal end of said light transmission system (32,82); a linear positional detector means (64) disposed in said light reception system (46,84), a visibility correction means (70,26,28), responsive to an output, from said linear positional detector means (64) for adjusting a position of said adjustable lens (10) of said optical system (12) of said viewfinder; reflection means (36,38,48,36A,38A) for partially commonly arranging the optical axes of said eye refractometer means (14,74) and said viewfinder; a first mask (42,88) disposed in conjugate relation with the pupil in said light transmission system (32,82) and having an opening (40;40A) around the optical axis thereof; a second mask (58,92) disposed in conjugate relation with the pupil in said light reception system (46,84) and having a pair of openings (54,56;54A,56A) in symmetrical relation with each other with respect to the optical axis thereof; wherein the respective openings (40,40A;54,54A;56,56A) of said light transmission system (32,82) and said light reception system (46,84) are arranged so as to allow luminous flux to pass therethrough without any overlapping; and said light reception system (46,84) includes a pair of symmetrical optical sub-systems disposed between said second mask (58,92) and said light source (30,80).

Claim 21

The viewfinder of claim 16, wherein said light transmission system (32,82) and said light reception system (46,84) have a common optical system from the retina to said second mask (58,92).

Claim 22

The viewfinder of claim 17, wherein said common optical system has a common optical axis, and said common optical system includes said adjustable lens (10) located on said common optical axis.

Claim 23

The viewfinder of claim 16, wherein a focal length from said adjustable lens (10) to the terminal end of said light reception system (46,84) is not greater than 17 mm.

Claim 24

The viewfinder of claim 16 or 17, wherein said eye refractometer means (14,74) includes a reduction lens (96) having at least one aspherical surface, said reduction lens (96) being disposed after said reflection means (36A,38A).

Claim 25

The viewfinder of claim 16, wherein said light source (30,80) comprises a near infrared light emitting diode having a light emitting region including a visible wavelength region.

Claim 26

The viewfinder of claim 16, wherein said eye refractometer means (14,74) includes an auxiliary lens (94) disposed just before said second mask (58,92) and having a first focal point at said second point or said other second point.

Claim 27

The viewfinder of claim 16, wherein said first mask (42,88) has an opening (40,40A) that is equal in configuration to the opening (54,56;54A,56A) of said second mask (58,92), said first mask (42,88) being located near to said light source (30,80).

Claim 28

The viewfinder of claim 18, wherein said adjustable lens (10) has at least one aspherical surface.