Abstract: A high power LED lamp has a GaN chip placed over an AlGaInP chip. A reflector is placed between the two chips. Each of the chips has trenches diverting light for output. The chip pair can be arranged to produce white light having a spectral distribution in the red to blue region that is close to that of daylight. Also, the chip pair can be used to provide an RGB lamp or a red-amber-green traffic lamp. The active regions of both chips can be less than 50 microns away from a heat sink.

Abstract: A high-power LED lamp uses an LED chip that can be larger than 1 mm square. The chip has trenches that can convert light trapped in the semiconductor into light that passes through a major surface of the chip. The trenches include light-reflecting tracks joined to a chip terminal and feeding a semiconductor layer. The chip can have triangular light emitting elements that improve light extraction from the semiconductor. The elements can be fused, resulting in improved manufacture yield of chips. A 25 watt single chip lamp with a heat sink very close to the active region is described.

Abstract: A high power LED lamp has a GaN chip placed over an AlGaInP chip. A reflector is placed between the two chips. Each of the chips has trenches diverting light for output. The chip pair can be arranged to produce white light having a spectral distribution in the red to blue region that is close to that of daylight. Also, the chip pair can be used to provide an RGB lamp or a red-amber-green traffic lamp. The active regions of both chips can be less than 50 microns away from a heat sink.

Abstract: A high-power LED lamp uses an LED chip that can be larger than 1mm square. The chip has trenches that can convert light trapped in the semiconductor into light that passes through a major surface of the chip. The trenches include light-reflecting tracks joined to a chip terminal and feeding a semiconductor layer. The chip can have triangular light emitting elements that improve light extraction from the semiconductor. The elements can be fused, resulting in improved manufacture yield of chips. A 25 watt single chip lamp with a heat sink very close to the active region is described.

Abstract: An LED color display matrix has first and second sets of LED lamps of first and second nominal color respectively. The actual colors of the lamps of the first set are not the same and this color mismatch is corrected for using the lamps of the second set.

Abstract: An LED light source for a lensed lamp is described. An LED chip sits in a hollow having a rectangular floor. A lower portion of the hollow has steep walls and accommodates the part of the chip that does not emit light. An upper part of the hollow has four side reflectors extending parallel to the sides of the chip and four corner reflectors. The hollow is formed by coining. The light source provides more uniform light than do previous arrangements having convergent lenses. The vertical viewing angle of the lamp is maintained throughout the whole of the horizontal viewing angle range of the lamp.

Abstract: A display matrix having LED lamps is arranged so that brightness variations between the lamps, due to the lamps having different characteristics from each other, is reduced. A process for setting up the display using an electronic camera is described. The system is arranged so that the brilliance of the lamps is automatically maximised when the sun is shining on the face of the display.

Abstract: A back illuminated array of display elements each of which comprises a vane rotatable between two positions by interaction between an electromagnet and a permanent magnet attached to the vane. The electromagnet includes a monolithic member of soft magnetic material having a U-shaped portion and a flange portion end is configured in such a way as to reduce the reluctance of the magnetic circuit comprised by the electromagnet and permanent magnet. The monolithic member can be arranged to provide a bearing for the rotatable vane.

Abstract: An electromagnetic display matrix includes easily replaceable modules mounted on a panel that is fitted with electromagnets, each module carrying an array of rotatable reflective vanes and a display sheet having an array of back-lit diffusers. The display sheet is removable by sliding it on the surface of the module, and the module is removable by sliding it on the surface of the panel. Tabs are provided by which the module can be released from the panel.

Abstract: A display system using a matrix of rotatable display elements is provided in which the optical states of the display elements can be read back to confirm that the matrix is portraying information correctly. The display system is arranged to automatically ameliorate the effect of detected non-operating display elements on the intelligibility of the message displayed.

Abstract: A display having a matrix of back-illuminated electromagnetically operated pixels. The display may be switched, by means of a movable light-passing sheet, between first and second modes of operation. In the first mode, the display is monochromatic and has a high resolution. In the second mode, color images are displayed but at a lower resolution.

Abstract: A matrix display of the back-illiminated electromechanical type has enhanced picture display features by including display elements whose brightness is individually adjustable.In one arrangement, each display element has an aperture and an opaque shutter selectively settable to each one of at least three stable positions. In one position, the shutter covers the aperture completely, and in the other positions, it uncovers the aperture to a differing extent so as to pass light of differing intensity depending on the position.The activating mechanism for the matrix display is a moving head having two magnetic actuators arranged side-by-side for each row of display elements. One magnetic actuator serves to accelerate the shutter of a selected display element, and the other applies a braking force to halt the shutter in the desired position so as to control the brightness of the display element.By providing a group (e.g.

Abstract: A stationary matrix panel has magnetic display elements arranged in vertical and horizontal rows, each element having two stable states of contrasting appearance. Electromagnetic actuator heads are mechanically coupled together by resilient couplings so as to move in unison and actuate selected display elements. The couplings are arranged to allow limited movement in a direction normal to that of the travel of the actuator heads across the matrix panel, thereby allowing for slight misalignment in the panel. Each actuator head contains a number of individual electromagnets and is responsive to a respective indexing track which provides signals indicative of the actual position of the actuation of the electromagnets in the head. The matrix panel has a plurality of guide rails arranged to provide accurate vertical registration of the heads, each guide rail being slotted to provide the indexing.

Abstract: A tooth cleaning instrument mounted at one end of a handle comprising a tapered blade of plastics material having a blunt apex folded about a base to apex line and inclined to the axis of the handle, the arrangement allowing all outer surfaces of the teeth as well as the spaces between them to be scraped to remove plaque and tartar. The other end of the handle can include a brush.

Abstract: An improved matrix display device is disclosed which includes a display matrix assembly having electromechanical display elements in horizontal rows and vertical columns. The assembly has two support portions extending the width of the assembly, one portion being at the top and the other being at the bottom. A rail member extends along the width of the matrix and is arranged to guide a movable electromagnetic head device. A series of hooks attach the rail member to one of the support portions at locations in the portion having a defined distance relative to each row of the matrix, thereby ensuring that the electromagnetic head device moves in registration with the rows of the matrix. A degree of resilience is included in the display device so as to apply tension between the support portions thereby maintaining the matrix assembly substantially flat. It is therefore unnecessary for the assembly to be made completely rigid, e.g. by including a sheet of glass, and the assembly may be left relatively flexible.