Optical switching device and image display device

• US 6,438,282 B1
• Filed: 11/14/2001
• Issued: 08/20/2002
• Est. Priority Date: 01/20/1998
• Status: Expired due to Term

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Yonekubo, Masatoshi, Kamijima, Shunji, Ito, Hirokazu, Takeda, Takashi
• Primary Examiner(s): Sangmau, Hemang
• Assistant Examiner(s): ROJAS, OMAR R
• Application Number:
  US09/991,336
• Publication Number:
  US 20020031294A1
• Time in Patent Office: 279 Days
• Field of Search: 385/16, 385/19, 385/901, 385/40, 359/290, 359/291, 359/295, 359/222, 359/223, 359/224
• US Class Current: 385/16
• CPC Class Codes: G02B 26/0816 by means of one or more reflecting elements
• CPC Class Codes: G09G 2300/06 Passive matrix structure, i.e. with direct application of both column and row voltages to the light emitting or modulating elements, other than LCD or OLED
• CPC Class Codes: G09G 2310/06 Details of flat display driving waveforms
• CPC Class Codes: G09G 3/3473 based on light coupled out of a light guide, e.g. due to scattering, by contracting the light guide with external means
• CPC Class Codes: Y10S 385/901 Illuminating or display apparatus

Abstract

An optical switching device comprises: a light guide including a total reflection plane capable of totally reflecting light thereby transmitting the light; a switching part capable of, at a position where its extraction plane is in close contact with the total reflection plane, capturing evanescent light and reflecting the captured light thereby outputting it; and a driving part for driving the optical switching part. The light guide, the switching part, and the driving part are laminated in this order into a multilayer structure. The employment of the multilayer structure makes it possible to optimize the respective layers independently of one another. The extracted light does not pass through the driving part. This allows the driving part to be optimized so as to achieve an optical switching device capable of operating at a high speed with low power consumption. Thus, it is possible to provide a low-loss and high-contrast optical switching device using an evanescent wave, which can respond at a high speed.

Claims

1. A method of controlling an optical switching device, said optical switching device comprising:

a light guide including a total reflection plane capable of totally reflecting input light thereby transmitting the light;

at least one switching part being in contact at a first position with the total reflection plane of said light guide, said switching part serving to extract evanescent light leaking through the total reflection plane, said switching part being capable of moving to a second position apart from said first position;

a supporting member for elastically supporting said switching part; and

electrostatic driving means including at least one pair of electrodes for driving said switching part,

wherein at least one of said electrodes is divided into a first part and a second part which are symmetric in shape to each other about the center of gravitation of said switching part,

said method comprising the step of supplying electric power to said first and second parts in such a manner that the timing of supplying the electric power is different between said first and second parts or voltages supplied to said first and second parts are different from each other.