Browse Prior Art Database

Liquid Crystal Lens with Specialized Elements

IP.com Disclosure Number: IPCOM000126802D
Original Publication Date: 2005-Aug-02
Included in the Prior Art Database: 2005-Aug-02
Document File: 3 page(s) / 72K

Publishing Venue

IBM

Abstract

This article desires to improve the concept of a liquid crystal lens by disclosing an internal dielectric layer, for improved heat dispersion and cooling. The spacer layer could alternately be a holographic filter, to filter out unwanted reflections from data layers in a multi-layer disk, when performing I/O with one of those data layers.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 41% of the total text.

Page 1 of 3

Liquid Crystal Lens with Specialized Elements

This article desires to improve the concept of a liquid crystal lens by disclosing an internal dielectric layer, for improved heat dispersion and cooling.

The spacer layer could alternately be a holographic filter, to filter out unwanted reflections from data layers in a multi-layer disk, when performing I/O with one of those data layers.

Figure 1 shows liquid crystal lens assembly 11, which comprises a front liquid crystal (LC) lens 13 which is proximal relative to optical media 95, a rear LC lens 15 which is distal relative to optical media 95, and a transparent spacer plate 17 separating lenses 13 and 15. A laser light source 19 (indicated schematically by the arrow) is projected into rear lens 15 from right to left, in the direction of the +X axis, through spacer 17, and then through front lens 13. Light source 19 is independently focused by each lens 13, 15 into beam 23, 25, respectively, and focused to a common point 21 or 21A to the left of front lens 13. The thickness of spacer plate 17 is selected to be one-half of one wavelength of the light emitted by light source 19. Light source 19 is preferably a blue-laser light source with a wavelength of 405 nm which is the wavelength being considered for both High Definition Digital Versatile Disk (HD-DVD) and Blu-Ray. However, other wavelengths could be used, such as red laser light at 650 nm which is used in today's Digital Versatile Disk (DVD).

FIG. 1 also shows a portion of an optical disk 95. Optical disk 95 rotates about the X-axis, and the Z-axis defines the radial direction along the optical disk. If optical disk 95 is either writable or re-writable, optical disk 95 may have grooves 97 and lands 98. Each groove 97 has sidewalls 96. Data is written to or read from data layer 99. Data layer 99 may comprise stamped pits for Read-Only-Memory (ROM). If data layer 99 is stamped pits, then grooves 97 and lands 98 are preferably absent. Alternately, data layer 99 may comprise magneto-optical media, phase-change media, or holographic media for the storage of data which can be rewritten, in which case grooves 97 and lands 98 are preferred. Also, data layer 99 may comprise phase-change, dye, or holographic media which is write-once, read-many (WORM), and again, grooves 97 and lands 98 are preferred. Optical disk 95 may comprise more than one data layer 99. For example, DVD-9 is dual-layer, single-sided optical media, and DVD-17 is dual-layer, dual-sided optical media.

Lenses 13, 15 are identical in construction and are illustrated in detail in FIG. 2. For simplicity, only lens 13 is discussed in FIG. 2, even though the following description applies equally to lens 15. Lens 13 consists of a pair of parallel, transparent plates 31, 33 and a plurality of thin, rectangular, insulative, polymer films 35 sandwiched perpendicular to plates 31 and 33. In the embodiment shown, plates 31, 33 are 1 mm squares. The inner surfaces of plates 31, 33 ar...