1.
    发明专利
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    公开(公告)号:DE1447208A1

    公开(公告)日:1969-10-16

    申请号:DE1447208

    申请日:1964-06-16

    Applicant: IBM

    Abstract: 1,061,257. Optical recording. INTERNATIONAL BUSINESS MACHINES CORPORATION. June 4, 1964 [June 28, 1963], No. 23118/64. Heading G5R. [Also in Division H4] A horizontal line of digital information is recorded on a vertically moving thermoplastic web 6, Fig. 1, by means of a light source 1, a rotating mirror 4 and an electrically responsive focus adjusting device 9 which causes focusing to be correct at every lateral point on the web, the device 9 being electrically linked to the mirror 4. The device 9 comprises a plate of electro-optic material, Fig. 4, not shown, which exhibits the " fringent electro-optic effect " when electrical voltages are applied between pairs of electrodes attached to its surfaces such that a Fresnel zone plate is defined by the gaps between fringent effect areas as they extend from the electrodes (see Division H4). The point of focus of a plane polarized monochromatic light beam is varied as the gaps between the fringent effect areas are caused to vary in response to the electrical voltages.

    METHODS OF TESTING FOR DIFFERENCES BETWEEN A SAMPLE PATTERN WITH A STANDARD USING HOLOGRAPHIC TECHNIQUES

    公开(公告)号:GB1248811A

    公开(公告)日:1971-10-06

    申请号:GB1166169

    申请日:1969-03-05

    Applicant: IBM

    Abstract: 1,248,811. Holography. INTERNATIONAL BUSINESS MACHINES CORP. March 5, 1969 [March 9, 1968], No. 11661/69. Heading G2J. A method of testing for differences between a sample pattern (e. g. a mask for making semiconductor wafers) and a standard pattern comprises forming a hologram 7 from a standard pattern 3 and a reference pattern 8 Fig. 3, illuminating the developed hologram 7h Fig. 4 with light that has passed through the sample pattern 12 so that any change in the resultant reconstructed reference pattern 11a 11b provides an indication of differences between standard and sample patterns. The hologram is formed by successive partial simultaneous exposures of the standard pattern and the reference pattern. The reference pattern 8 preferably comprises a pair of pin holes 8a, 8b, and the standard pattern 3, comprises three known pattern 3a, 3b, 3c, corresponding to the samples to be tested. Pattern 3b need not be used. The reference pattern 8a, 8b is reconstructed as pattern 11a 11b. If desired the reference pattern could be a point having a concentric circle the circumference of which formed the limits of acceptable deviation of the pin hole. In a further embodiment useful where large numbers of samples have to be evaluated the reconstructed image illuminates a digital light deflector which can be measurably adjusted to cancel out the deviation in the sample.

    IMPROVEMENTS IN OR RELATING TO OPTICAL DEFLECTION APPARATUS

    公开(公告)号:GB1299349A

    公开(公告)日:1972-12-13

    申请号:GB1465570

    申请日:1970-03-26

    Applicant: IBM

    Abstract: 1299349 Deflecting light INTERNATIONAL BUSINESS MACHINES CORP 26 March 1970 [5 April 1969] 14655/70 Heading H4F In a light deflector formed of a plurality of stages each comprising an element which deflects an incident light beam in one of two directions depending on its plane of polarization, e.g. a Wollaston prism, and electro-optical means for varying the plane of polarization of the light beam, the position of each deflecting element is unimportant when the deflector is used for a collimated light beam and in conjunction with an objective lens since the final position of the deflected beam in the focal plane of the lens depends only on the angle, and not on the actual position, at which the beam is incident on the lens. In such a case the deflector causes the light source to appear as a selected one of a series of equi-angularly disposed virtual sources at infinity i.e. if the splitting angles of successive prisms form a binary progression. If however it is desired to deflect an image in a plane 16 to a series of equidistant positions in an object plane of a lens 17, the reasoning above does not apply since the source of light is not at infinity and the light from any point of the image diverges and converges before and after the lens respectively and it is necessary to arrange that the final deflected beams 1-8 generate equidistant virtual images in the plane 16. This is done either by modifying the deflection angles of the prisms so that they do not form a true binary series, i.e. coarse adjustment during manufacture, or by varying the distance of each prism from the plane 16 (fine adjustment when setting up), since these two quantities are interdependent. In a preferred embodiment the virtual images 4a, 10a, 13a generated by the beams 4, 10, 13 least deflected from the optical axis after every stage are spaced from the intersection of the optical axis 15 and plane 16 by relative distances corresponding to a binary series. The lens 17 may also be disposed between the deflector W0, W1, W2 and the plane 16. The Specification includes details of how to calculate the desired angles and positions of the prisms W0, W1, W2, including the case when the deflector is immersed in oil.

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