EP0195657A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Optical pickup
Assignee: Fujitsu Ltd
•
Filing: 1986-03-19
•
Granted: —
•
Expires: 2006-03-19
Abstract
Abstract An optical pickup for reading out information from an information recording medium, such as an optical diskette, comprises a light source (11) for irradiating a light beam (L,) onto an optical diskette (D), an optical sensor (15) for detecting a light beam (L 10 ) reflected from the optical diskette, and an optical system including a wave plate and two hologram lenses (12,13). The first hologram lens (13) diffracts the light beam (L 7 ) from the light source, and the second hologram lens (12) transmits the same light beam (L 7 ). On the other hand, the second hologram lens (12) diffracts the reflected light beam (L 10 ) from the optical diskette (D) towards the optical sensor (15), and the first hologram lens (13) transmits the same reflected light beam. (L 10 ). The light and compact- sized hologram lenses (12,13) enable a reduction in the access time to the optical diskette (D). A hologram lens assembly, suitable for use in an optical pickup, is also disclosed.
Inventors
- 👤 Masayuki Kato
- 👤 Fumio Yamagishi
- 👤 Shin-Ya Hasegawa
- 👤 Hiroyuki Ikeda
- 👤 Takefumi Inagaki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 21:26
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/12; G11B7/135; G11B7/1353; G02; G02B; G02B5/00; G02B5/32; G11B7/08; G11B7/085; G11B7/08547; G11B7/1365; G11B7/1372
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
212 words
An optical pickup comprising a light source for irradiating a light beam onto an information recording medium, such as an optical diskette, an optical sensor for detecting the light beam reflected by said information recording medium, and an optical lens system including a wave plate through which said light beam may pass, characterised in that the optical lens system further comprises: a first hologram lens; and a second hologram lens arranged substantially parallel to said first hologram lens; said first and second hologram lenses and said wave plate being arranged such that, in use, the light beam irradiated from said light source passes through said first and second hologram lenses in turn and said wave plate, the light beam is then reflected at said information recording medium, and the reflected light beam again passes through said wave plate and the second and first hologram lenses, in turn; one of said first and second hologram lenses diffracting the light beam from said light source towards said information recording medium, and transmitting the reflected light beam from said information recording medium; and the other of said first and second hologram lenses transmitting the light beam from said light source, and diffracting the reflected light beam from said information recording medium towards the optical sensor.
Claim 2
Dependent Claim
212 words
An optical pickup comprising a light source for irradiating a light beam onto an information recording medium, such as an optical diskette, an optical sensor for detecting the light beam reflected by said information recording medium, and an optical lens system including a wave plate through which said light beam may pass, characterised in that the optical lens system further comprises: a first hologram lens; and a second hologram lens arranged substantially parallel to said first hologram lens; said first and second hologram lenses and said wave plate being arranged such that, in use, the light beam irradiated from said light source passes through said first and second hologram lenses in turn and said wave plate, the light beam is then reflected at said information recording medium, and the reflected light beam again passes through said wave plate and the second and first hologram lenses, in turn; one of said first and second hologram lenses diffracting the light beam from said light source towards said information recording medium, and transmitting the reflected light beam from said information recording medium; and the other of said first and second hologram lenses transmitting the light beam from said light source, and diffracting the reflected light beam from said information recording medium towards the optical sensor.
Claim 3
Dependent Claim
35 words
An optical pickup as set forth in claim 1, wherein said one of said hologram lenses diffracts the light beam from said light source so as to directly focus it on said information recording medium.
Claim 4
Dependent Claim
37 words
An optical pickup as set forth in claim 1 or 2, wherein said other of said hologram lenses diffracts the reflected light beam from said information recording medium so as to focus it on said optical sensor.
Claim 5
Dependent Claim
22 words
4 . An optical pickup as set forth in claim 1 ,2, or 3, wherein said light source is a semiconductor laser.
Claim 6
Dependent Claim
58 words
An optical pickup set forth in any preceding claim, wherein said first or second hologram lens consists of a phase hologram, which in use transmits the light beam by irradiating it at the non-Bragg angle and diffracts the light beam by irradiating it at the Bragg angle, and the other hologram lens consists of a surface relief hologram.
Claim 7
Dependent Claim
22 words
An optical pickup as set forth in claim 1,2,3, or 4 wherein both said first and second hologram lenses consist of phase
Claim 8
Dependent Claim
51 words
holograms, the hologram lens adjacent the optical diskette when in use transmits or diffracts the light beam by irradiating it at the non-Bragg or Bragg angle, and the other hologram lens when in use transmits or diffracts the light beam by irradiating it at the non-Bragg angle, or by P-or S-polarization.
Claim 9
Dependent Claim
51 words
holograms, the hologram lens adjacent the optical diskette when in use transmits or diffracts the light beam by irradiating it at the non-Bragg or Bragg angle, and the other hologram lens when in use transmits or diffracts the light beam by irradiating it at the non-Bragg angle, or by P-or S-polarization.
Claim 10
Dependent Claim
24 words
An optical pickup as set forth in claim 1,2,3, or 4, wherein both said first and second hologram lenses consist of surface relief holograms.
Claim 11
Dependent Claim
40 words
An optical pickup as set forth in claim 7, wherein said first and second surface relief hologram lenses have relief grooves, and the relief grooves of the first hologram lens are arranged parallel to those of the second hologram lens.
Claim 12
Dependent Claim
40 words
An optical pickup as set forth in claim 7, wherein said first and second surface relief hologram lenses have relief grooves, and the relief grooves of the first hologram lens are arranged perpendicular to those of the second hologram lens.
Claim 13
Dependent Claim
58 words
An optical pickup as set forth in any preceding claim, wherein one of said first and second hologram lenses when in use diffracts the light beam from said light source to form a parallel light beam, and said optical lens system further comprises an objective hologram lens for focussing said parallel light beam on said information recording medium.
Claim 14
Dependent Claim
27 words
An optical pickup as set forth in claim 10, wherein said objective hologram lens is a double-structured inline hologram lens symmetrical with respect to its optical axis.
Claim 15
Dependent Claim
88 words
A hologram lens assembly comprising: a first hologram lens ; and a second hologram lens arranged substantially parallel to said first hologram lens ; such that, in use, light passing through said first and second hologram lenses in turn is diffracted by one of said hologram lenses, and is transmitted by the other of said hologram lenses; and light passing through said second and first hologram lenses in turn is transmitted by said one of said hologram lenses, and is diffracted by said other of said hologram lenses.
Claim 16
Dependent Claim
88 words
A hologram lens assembly comprising: a first hologram lens ; and a second hologram lens arranged substantially parallel to said first hologram lens ; such that, in use, light passing through said first and second hologram lenses in turn is diffracted by one of said hologram lenses, and is transmitted by the other of said hologram lenses; and light passing through said second and first hologram lenses in turn is transmitted by said one of said hologram lenses, and is diffracted by said other of said hologram lenses.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.