GB2035595A

GB2035595A - Optical positioning apparatus

Info

Publication number: GB2035595A
Application number: GB7846442A
Authority: GB
Original assignee: GE Healthcare UK Ltd
Current assignee: GE Healthcare UK Ltd
Priority date: 1978-11-29
Filing date: 1978-11-29
Publication date: 1980-06-18
Also published as: GB2035595B

Abstract

A method for accurately placing a microlens 10 on an element 22 (preferably a light emitting device) comprises holding the lens 10 by suction on the end of a hollow glass fibre or capillary tube 11, illuminating the element 22 and moving it until the Illumination transmitted along the fibre is of uniform distribution. The lens 10 is then stuck to the element 22. As shown, the element 22 is moved by an X-Y table 24, and the fibre 11 is raised and lowered by a micrometer (not shown). illumination from the fibre 11 is viewed through a microscope 26 e.g. by a sensor (not shown) which controls movement of table 24. <IMAGE>

Description

SPECIFICATION Optical positioning apparatus The present invention relates to light emitting devices and more particularly to a method and apparatus for positioning a microlens onto a light emitting device.

According to the present invention there is provided a method of positioning an optical element onto an emitting and/or receiving region which includes the steps of picking up an optical element in a vacuum attachment, said attachment comprising a length of optical fibre having associated therewith a vacuum line such that on operation of said vacuum line one face of the optical element adheres to one end of the optical fibre; attaching an adhesive substance onto another face of the optical element; illuminating the emitting and/or receiving region such that the illumination is capable of being transmitted via the optical element along said fibre; lowering said optical element onto said region, moving the element in relation to the region until the image of illumination transmitted along the optical fibre is of a substantially uniform intensity distribution when said region and said element are axially aligned; allowing adhesive to cure; removing said optical fibre by means of cessation of the generation of the vacuum line.

The invention also provides apparatus for effecting the above method.

Embodiments of the present invention will now be described, by way of example with reference to the accompanying drawings, in which:~ Figure 1 shows in detail the method of holding the microlens and, Figure 2 shows the apparatus for positioning the microlens with respect to the light emitting device.

Referring now to Figure 1, there is shown a microlens 10 and a glass capillary tube or hollow glass fibre 11. The microlens 10 is held on the end of the tube 11 by evacuation of the tube 11. The microlens is formed with a flat surface 12 which in the finished article will sit on top of the light emitting device which will normally have a substantially flat light emitting surface. The microlens may, therefore, be picked up in the correct orientation by placing it on a flat surface rolling it until the flat surface 12 abuts the flat surface and then lowering the tube 11 until it touches the top of the microlens 10 and then applying the vacuum to the tube 11.

Referring now to Figure 2 the lens 10 is shown attached to the tube 11. The tube 11 is connected to a further tube 20 which is rigidly attached to a support 21 which support is capable of movement in a vertical direction by micrometer screw means (not shown). The light emitting device 22 is placed on a tray 23 attached to a table 24 by support means 25.

The table 24 is capable of movement in the X-Y directions.

A microscope 26 is placed immediately above the tube 11.

The method of lens placement is as follows. The lens is picked up as described and held in the tube 11 by a vacuum applied through tube 20. The flat end 12 of the lens is smeared with an adhesive e.g. epoxy resin. The lens is lowered by the micrometer screw on support 21 until it is just above the surface of the light emitting device 22 which is switched on. The operator looks down the microscope 26 and the table 24 is moved in the X and Y directions until the light rays 13 (Figure 1) form a symmetrical pattern.

When this occurs the lens 10 is lowered onto the light emitting device 22 and held there until the resin has partially set. The vacuum is then released and the lens and device assembly removed carefully from the tray 23. The next device is then placed on the tray and the process repeated.

The microscope and control the of the X and Y movement of the table 24 could be carried out automatically by a pattern sensing device or maximum light input device mounted to view the microscopic image and with electronic outputs to control stepping motors to control the table 24 in both X and Y directions.

Claims

1. A method of positioning an optical element onto an emitting and/or receiving region which includes the steps of picking up an optical element in a vacuum attachment, said attachment comprising a length of optical fibre having associated therewith a vacuum line such that on operation of said vacuum line one face of the optical element adheres to one end of the optical fibre; attaching an adhesive substance onto another face of the optical element; illuminating the emitting and/or receiving region such that the illumination is capable of being transmitted via the optical element along said fibre; lowering said optical element onto said region, moving the element in relation to the region until the image of illumination transmitted along the optical fibre is of a substantially uniform intensity distribution when said region and said element are axially aligned; allowing adhesive to cure; removing said optical fibre by means of cessation of the operation of the vaccuum.

2. A method of positioning an optical element as claimed in claim 1 in which the optical fibre is a hollow glass fibre.

3. Apparatus for positioning an optical element onto an emitting and/or receiving region in accordance with the method of claim 1 said apparatus comprising a length of optical fibre or fine glass capillary tube, a vacuum generator attached to a vacuum tube, such tube being attached to one end of said length of optical fibre or capillary tube, for evacuating said fibre or tube, means for holding said fibre or tube in a vertical position and means for moving said fibre or capilliary tube vertically and horizontally, and including control means for said vacuum tube means for applying and removing the vacuum to said vacuum tube to pick up and place a lens held to said optical fibre or capilliary tube by said vacuum, means for viewing light transmitted along said optical fibre and said optical element or capilliary tube and means for determining when the distribution of said light is substantially uniform and for removing the vacuum to deposit said optical element onto said emitting or receiving region.

4. A method of positioning an optical element onto an emitting or receiving region substantially as described with reference to'the accompanying drawings.

5. Apparatus for positioning an optical element onto an emitting or receiving region substantially as described with reference to the accompanying drawing.