JPH04163521A - Optical coupler - Google Patents

Abstract

PURPOSE:To secure such an optical coupler that is high in light utilization efficiency by changing a mask pattern to a phase modulation type hologram recorded in a liquid crystal light bulb. CONSTITUTION:A laser beam bundle 107 emitted out of a laser beam source 101 turns to a parallel beam expanded by a collimator lens 102, and it is inci dent into a liquid crystal light bulb 103. Then, a wave surface is modulated by action of a computer hologram recorded in the liquid crystal light bulb and, after passing through a lens 105, a wiring pattern 108 is formed in a light receiving part 109 on an electric circuit element 106. This light receiving part is made of an optical rewriting material, through which electric conductivity is varied according to the extent of laser irradiation, serving as wiring for an electric circuit, and if this laser irradiation is stopped, the wiring vanishes into nothing. With this constitution, such an optical coupler that is high in light utilization efficiency in a coherent illuminant and rewritable is securable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an optical coupling device using a liquid crystal light valve.

[Prior Art] A conventional optical coupling device uses a reduction projection method of an immersion mask pattern as shown in FIG. Incoherent light 607 emitted from a lamp 601 and passed through a TN (twisted nematic) mode liquid crystal display element 603 on which an immersion mask with the same pattern as the wiring pattern 108 is recorded is focused by a lens 105 onto an optical rewriting material 609. irradiate.

[Problems to be Solved by the Invention] However, since the conventional optical coupling device uses a projection type wet liquid mask pattern, there is a problem in that the light utilization efficiency is low. Therefore, an object of the present invention is to provide an optical coupling device with high light utilization efficiency by replacing the mask pattern with a phase modulation type hologram recorded on a liquid crystal light valve.

[Means for Solving the Problems] The optical coupling device of the present invention includes an ECB mode liquid crystal light valve, a pattern generator for recording a hologram pattern on the light valve, and a plurality of input/output terminals using an optical rewriting material. and a coherent light source for reproducing a hologram diffraction image onto the optical rewriting material.

A second optical coupling device of the present invention is characterized in that, in the first optical coupling device, the ECB mode liquid crystal light valve is of an active matrix type.

A third optical coupling device of the present invention is characterized in that, in the first or second optical coupling device, the optical rewriting material utilizes a local change in refractive index.

A fourth optical coupling device of the present invention is characterized in that, in the first to third optical coupling devices, the optical rewriting material utilizes a local change in conductivity.

A fifth optical coupling device of the present invention is characterized in that in the first to fourth optical coupling devices, the coherent light a is at least two or more coherent light sources having different oscillation wavelengths.

[Example code] Hereinafter, the details of the present invention will be shown by examples.

FIG. 1 shows the configuration of the optical coupling device of the present invention. A laser beam bundle 107 emitted from the laser light source 101 becomes parallel light that is expanded by the collimating lens 102 and enters the liquid crystal light valve 103 . Then, the wavefront is modulated by the action of a computer-generated hologram recorded on the liquid crystal light valve, and after passing through the lens 105, a wiring pattern 108 is formed on the light receiving section 109 on the electric circuit element 106. This light-receiving section is made of an optically rewritten material (amorphous silicon in this case), and changes its conductivity in response to laser irradiation, and is used to wire electrical circuits. When the laser irradiation is stopped, the wiring disappears immediately.

FIG. 2 shows another configuration example. Instead of the electric circuit element in FIG. 1, an optical circuit element 208 using an optical rewriting material is used as a component. Here, as an optical rewriting material, an electro-optic crystal material whose refractive index changes depending on light (here, B i
12S i 020) was used.

To erase the recorded wiring pattern, it is irradiated with laser light of a different wavelength from that used when it was recorded. In FIG. 2, a dichroic prism 203 is used to make two lasers 206 and 207 having different oscillation wavelengths have a common optical axis. Then, the oscillation of the two lasers was controlled by signals from the pattern generator 104.

A pattern generator 104 for recording a hologram on the liquid crystal light valve 103 stores hologram pattern data created by a computer in advance. By doing this, it was possible to generate various patterns instantly.

FIG. 3(a) is a schematic diagram showing the appearance of the liquid crystal light valve 103. This liquid crystal light valve has the following features.

(1) Crosstalk between pixels is eliminated by adding polysilicon TPT to each pixel as an active element.

(2) It is a built-in driver type that takes advantage of the characteristics of polysilicon TPT, and is small in size.

(3) 19x13 display area 302 horizontally 320
, has 220 pixels in the vertical direction.

FIG. 3(b) is a schematic diagram showing the pixel structure of a liquid crystal light valve. Here, it is important that the pixels 311 are arranged at regular intervals in both the horizontal and vertical directions and in a grid pattern. By using a liquid crystal light valve having such characteristics, it has become possible to freely generate a wiring pattern with a desired intensity distribution.

Further, the computer generated hologram functioning in the optical device of this embodiment is a phase modulation type Fourier transform hologram,
One Fourier transform value (phase component) corresponds to one pixel.

With this configuration, it is possible to record a computer-generated hologram on the liquid crystal light valve by effectively utilizing the limited number of pixels, and to reproduce a wiring pattern from this hologram with almost 100% light utilization efficiency. It's now possible.

The liquid crystal light valve shown in FIG. 3 consists of an ECB (electric field controlled birefringence) mode liquid crystal panel and one polarizing plate placed on the side of the panel into which laser light is incident. The initial orientation of liquid crystal molecules in a liquid crystal panel is uniformly horizontal to the panel substrate. Further, the transmission axis of the polarizing plate is parallel to the plane formed by the panel substrate and the long axis direction of the liquid crystal molecules.

The TPT and other circuit elements are arranged under the light-shielding mask 312 to prevent malfunctions caused by light irradiation. By adopting such a structure, it became possible to effectively utilize the birefringence change of the liquid crystal layer with respect to the applied voltage, and it was possible to obtain good phase modulation characteristics for the laser beam flux.

FIG. 4 shows the relationship between phase change and applied voltage obtained from an ECB mode liquid crystal light valve.

FIG. 5 shows an example of a wiring pattern. FIG. 5(a) shows a basic form in which input/output terminals 501 are connected by a wiring pattern 503 recorded on an optical rewriting material 502.

As shown in FIG. 5(b), a plurality of wirings can be performed simultaneously.6 FIG. 5(C) is an example of a directional coupler in an optical circuit. Even when there are a plurality of optical rewriting materials 502 connected to one element by optical or electric circuits 511 as shown in FIG. 5(d), wiring can be performed at the same time.

Note that although a plurality of laser light sources are used here for writing and erasing patterns on the optical circuit element, a variable wavelength laser may be used instead.

[Effects of the Invention] As described above, according to the present invention, due to the action of the phase modulation computer generated hologram recorded on the liquid crystal light valve,
This has the effect of providing a rewritable optical coupling device with high light utilization efficiency of a coherent light source. Furthermore, if a wavelength tunable laser is used, errors in wiring pitch can be corrected simply by changing the wavelength. Additionally, since a hologram is used, it is less likely that the pattern will be disconnected or shorted due to dirt or dust on the mask surface.

In addition to the above, the present invention can be widely applied to optical switches, optical information processing, etc.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the configuration of the optical coupling device of the present invention. FIG. 2 is a perspective view showing another configuration of the optical coupling device of the present invention. FIG. 3(a) is a plan view showing the appearance of the liquid crystal light valve. FIG. 3(b) is a plan view showing the pixel structure of the liquid crystal light valve. FIG. 4 is a diagram for explaining the phase modulation characteristics of a liquid crystal light valve. FIGS. 5(a) to 5(d) are plan views showing examples of wiring patterns. FIG. 6 is a perspective view showing the configuration of a conventional optical coupling device. 101 Laser light source 102 Collimating lens 103 Liquid crystal light valve 104 Pattern generator 105 Lens 106 Electric circuit element 107 Laser beam bundle 108 Wiring pattern 109 Light receiving section 201 Laser light source 202 Collimating lens 203 Dichroic prism 204 Laser light source 205 Collimating lens 206 Laser beam bundle 207 Laser Light beam bundle 208 Optical circuit element 301 Liquid crystal light valve 302 Display area 311 Pixel 312 Light-shielding mask 501 Input/output terminal 502 Optical rewriting material 503 Wiring pattern 511 Circuit 601 Lamp 603 Liquid crystal display element 607 Incoherent light 609 Optical rewriting material Applicant Seiko Epson Corporation Agent Patent Attorney Kizobe Suzuki (1 person) 101 Cisa°
Mitsu Jun Shu 1 Figure 30 (a) Paper 30 (shi) Input O Voltage 4 Figure 6

Claims (5)

[Claims] (1) Regarding optical coupling devices using optically rewritable materials, EC
A B (field-controlled birefringence) mode liquid crystal light valve, a pattern generator for recording a hologram pattern on the light valve, an element having multiple input/output terminals using an optical rewriting material, and a hologram diffraction image recording device. An optical coupling device comprising: a coherent light source for reproducing onto an optical rewriting material. (2) The optical coupling device according to claim 1, wherein the ECB mode liquid crystal light valve is of an active matrix type. (3) The optical coupling device according to claim 1 or 2, wherein the optical rewriting material utilizes a local change in refractive index. (4) Claim 1, Claim 2, or Claim 3, wherein the optical rewriting material utilizes a local change in conductivity.
The optical coupling device described. (5) The optical coupling device according to claim 1, 2, 3, or 4, wherein the coherent light source is at least two coherent light sources having different oscillation wavelengths.