Patent EP0176334A2 successfully refreshed from Google Patents.
EP0176334A2
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EP
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Optical low pass filter
Assignee: Sony Corp
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Filing: 1985-09-23
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Granted: —
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Expires: 2005-09-23
Abstract
Abstract An optical low pass filter (10) used in a video camera having a solid state image sensing device and a color separating filter is disclosed, which includes a first double refraction plate (10A) being arranged to separate an incident light ray to an ordinary light ray (0,) and an extraordinary light ray (e 1 ,) which is displaced from the ordinary light ray (0 1 ) by a distance d in a directon with the angle substantially equal to 8 relative to the horizontal direction (H) of the solid state image sensing device, wherein and a second double refraction plate (10B) being arranged to separate an incident light ray to an ordinary light ray (O 2 ) by a distance d in a direction with the angle substantially equal to -θ relative to the horizontal scanning direction (H) of the solid state image sensing device, whereby the optical low pass filter (10) has the spatial frequency characteristic having a first trap frequency u 1 and a second trap frequency 2u,.
Inventors
- 👤 Yasuo Nakada
- 👤 Masuko Amemiya
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 22:01
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/42; G02B27/46
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
208 words
An optical low pass filter for use in a video camera comprising a solid state image sensing device (Figs. 1A and 3A) and a color separating filter (Figs 1B and 3B), said optical low pass filter characterised by: a first double refraction plate (10A) arranged to separate an incident light ray to an ordinary light ray (9) and an extraordinary light ray (e 1 ) which is displaced from said ordinary light ray (9) by a distance d in a direction with an angle substantially equal to θ relative to the horizontal scanning direction (H) of said solid state image sensing device, wherein cos 2θ=√2 3 (0°<2θ<90°), and a second double refraction plate (10B) arranged to separate an incident light ray to an ordinary light ray (0 2 ) and an extraordinary light ray (e 2 ) which is displaced from said ordinary light ray (0 2 ) by a distance d in a direction with an angle substantially equal to -0 relative to the horizontal scanning direction (H) of said solid state image sensing device (Figs. 1A and 3A), whereby said optical low pass filter (10) has the spatial frequency characteristic having a first trap frequency u 1 and a second trap frequency 2u 1 (Fig. 9A).
Claim 2
Dependent Claim
208 words
An optical low pass filter for use in a video camera comprising a solid state image sensing device (Figs. 1A and 3A) and a color separating filter (Figs 1B and 3B), said optical low pass filter characterised by: a first double refraction plate (10A) arranged to separate an incident light ray to an ordinary light ray (9) and an extraordinary light ray (e 1 ) which is displaced from said ordinary light ray (9) by a distance d in a direction with an angle substantially equal to θ relative to the horizontal scanning direction (H) of said solid state image sensing device, wherein cos 2θ=√2 3 (0°<2θ<90°), and a second double refraction plate (10B) arranged to separate an incident light ray to an ordinary light ray (0 2 ) and an extraordinary light ray (e 2 ) which is displaced from said ordinary light ray (0 2 ) by a distance d in a direction with an angle substantially equal to -0 relative to the horizontal scanning direction (H) of said solid state image sensing device (Figs. 1A and 3A), whereby said optical low pass filter (10) has the spatial frequency characteristic having a first trap frequency u 1 and a second trap frequency 2u 1 (Fig. 9A).
Claim 3
Dependent Claim
25 words
An optical low pass filter (10) according to claim 1, wherein said first and second double refraction plates (10A and 10B) are made of crystal.
Claim 4
Dependent Claim
24 words
An optical low point pass filter (10) according to claim 1, wherein said first and second double refraction plates (10A and 10B) are laminated.
Claim 5
Dependent Claim
60 words
An optical low pass filter according to claim 1, wherein said distance d is selected such that said first trap frequency u 1 is where Px is a horizontal pitch of the image sensing unit of said solid state image sensing device (Fig. 1A), and said color separating filter (Fig. 1B) has a triplet pattern in the horizontal scanning direction.
Claim 6
Dependent Claim
66 words
An optical low pass filter according to claim 1, wherein said distance d is selected such that said first trap frequency u 1 is where Px is a horizontal pitch of the sensing unit of said solid state image sensing unit of said solid state image sensing device (Fig. 3A), and said color separating filter (Fig. 3B) has a doublet pattern in the horizontal scanning direction.
Claim 7
Dependent Claim
51 words
A video image pick up device comprising an image pick up element of the type which performs spatial sampling of an image via a color separating filter, characterised in that the device includes a filter according to any one of the preceding claims to filter light passing to the separating filter.
References Cited (Backward Citations)
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