5mm LED: Epoxy Lamp with a Reflector-Cup Lead Frame (Kosman, US 3,821,590, 1974)

A round LED indicator lamp about 0.200 in (5 mm) across. A red GaP chip sits on a small pedestal at the focus of a paraboloid reflector cup that is part of the lead frame. A fine wire runs from the chip to the other lead. The whole is moulded in clear or tinted epoxy, with small lenses moulded into the front face to spread the light. Result: an encapsulated LED lamp visible within about ±45°, moulded many at a time on one lead frame. Source: K. J. W. Kosman and L.-P. Boivin (Northern Electric), US 3,821,590 (1974). Unknown: lead and wire metals, die attach and cure. Picture: the patent drawing.

خبير

Unknown

التعليمات

Make the lead frame with its reflector

Make a lead frame carrying many lamps. In each, the negative lead ends in a paraboloid reflector cup with a small pedestal at its focus, and the positive lead ends nearby. Not given: the metal, sizes beyond the lamp's 0.200 in diameter.

المواد لهذه الخطوة:

معدن غير معروف1 lead frame

الأدوات المطلوبة:

أبعاد غير معروفة

Mount and bond the chip

Mount a light-emitting chip with a P-N junction, for example red GaP:Zn,O, on the pedestal, so the cup makes contact with one side of the junction. Connect the other side by a fine wire to the positive lead. About 0.015 in square is the junction size Kosman gives for best efficiency. Not given: the die attach, the wire metal.

المواد لهذه الخطوة:

شريحة LED1 light-emitting chip

معدن غير معروف1 bond wire

الأدوات المطلوبة:

أبعاد غير معروفة

Transfer-mould the lamps

Set the bonded lead frame in a mould and transfer-mould clear or tinted thermosetting resin round all the lamps at once, front face down so any flaws fall at the back. The front face carries seven spherical lenses, six in a ring round one, each 0.045 in across with a radius about 0.8 times its width; an inclined edge sends some light out sideways. Ours: bisphenol epoxy (the patent lists epoxy, silicone, polyester or diallyl phthalate). Not given: the mould, the cure.

المواد لهذه الخطوة:

راتنج إيبوكسي من البيسفينول1 capsule resin

الأدوات المطلوبة:

مكبس قولبة بالنقل

طريقة تشكيل مجهولة

Cut apart and test

Cut the lamps from the lead frame and light each one with current forward through the junction: the face shows seven bright spots in a 0.100 in image, visible up to about 45° off axis. Not given: the current.

الأدوات المطلوبة: