WO2003030132A1

WO2003030132A1 - A display and method of manufacture

Info

Publication number: WO2003030132A1
Application number: PCT/CN2001/001464
Authority: WO
Inventors: Tong Fatt Chew; Senggeap Goh; Dianwei Liu; Roger Suen; Kenny Chow; Sidney Chu
Original assignee: Agilent Technologies, Inc.; Cotco International Limited
Priority date: 2001-09-29
Filing date: 2001-09-29
Publication date: 2003-04-10
Also published as: CN1488128A; CN1228749C

Abstract

An surface mount seven segment LED display comprises a rectangular reflector body (70) and an 'I' shaped PCB (50). The PCB has positioning holes, holes for epoxy and conductive holes. The PCB (50) has a pair of V-shaped recesses (61) towards its shorter edges. The reflector body (70) has a flat front face (70a) and a hollow inner area (70b) and rear side walls (72, 78). The hollow inner area includes locator pins (71) for fixing the PCB (50). Further the reflector has a pair of ridges (73) on its ends to hold the recesses (61) of the PCB (50). The assembly of a compact reflector and a thin PCB is encapsulated by a resin/hardener epoxy.

Description

A DISPLAY AND METHOD OF MANUFACTURE

FIELD OF THE INVENTION

The present invention relates to displays and a method of manufacturing them. In particular it relates to surface mount light emitting displays and, more particularly, although not necessarily solely, to seven-segment surface mount light emitting displays.

BACKGROUND OF THE INVENTION

Multi-segment displays such as seven-segment displays are used in many electronic devices for visually indicating the user with a specific numeric or alphanumeric character. Currently seven-segment displays are available in various dimensions and colours. The colours usually available are green, red, orange, white and yellow. However, displays in other colours are possible and it depends on the user's requirement.

Usually a single digit display consists of seven generally rectangular segments with light emitting diodes arranged in the shape of an '8'. By lighting up different combinations of segments from the seven segments, different symbols are created on the display. Sometimes, there is also a smaller, circular light emitting segment placed adjacent to the seven segments. The seven segments are used to indicate numerical as well as alphanumeric characters, while the smaller light emitting segment is used for a decimal point or a full-stop indication.

A known seven segment display is described with reference to figures 1 to 4. Figure 1 shows the front view of such a display. Figure 2 shows a perspective view from the rear and to the side. Figure 3 is a cross-section along the length of a display, looking from the side. Figure 4 shows known circuit diagrams for such displays. The display has three main parts, a rectangular reflector body (10), a rectangular printed circuit board (PCB) (20) and translucent epoxy resin (30).

The reflector body of moulded plastic (10) has a front face (11), two side walls and two end walls but no back. It is hollow, forming a cavity (12). The front face (11) has seven rectangular segment holes in it (13a-13g) and a round hole (13h), which extend from the front (11a) to the back (l ib) of the front face (11), into the cavity (12). These seven segment holes (13a-13g) are elongate, being the shape of the seven display segments. They are also longer at the front (1 la) than at the rear (1 lb) of the front face (11), as the elongate holes (13a-13g) get gradually longer, the nearer to the front face (11 a).

PCB (20) has a front face (21) and a rear face (22). The front face has eight light emitting diodes (23a-23h) on it. These diodes are spaced apart with circuitry, well known in the art, to allow them to be activated and to light up as and when required by controlling circuitry, to produce desired combinations of diodes lit up simultaneously. The terminals for the various circuits shown in Figure 4 are connected to, in this case, ten wire pins (24a-24j), which extend backwards from the rear face of the PCB (20).

The PCB (20) is sited in the reflector body (10), in the cavity (12). It is shaped and the eight diodes (23a-23h) are arranged such that each diode (23a-23h) is immediately behind a corresponding segment hole (13a-13g) or round hole (13h). Therefore, when a diode (23a-23h) is activated, its light can be seen from in front of the reflector body (10), through the corresponding hole (13a-13h).

The epoxy resin (30) is also in the cavity (12) of the reflector body (10). It fills the eight holes (13a-13h). It fills the gap between the rear (1 lb) of the front face (11) and the front (21) of the PCB (20). It also passes around the edges of the PCB and covers its rear face (22). The resin not only works to diffuse the light from the diodes (23a- 23h) to the front of the holes (13a-13h), but it also works.to seal the gap between the front (21) of the PCB 20 and the rear (l ib) of the front face (11) of the reflector (10) and to seal the PCB (20) in place.

Figure 4 shows known internal circuit diagrams of two types of LED displays, common anode and common cathode. One end of each of the eight light emitting diodes (23a-23h) is usually connected to form either a common anode or a common cathode format. By selectively connecting the relevant driving pins (24a-24j) of the individual light emitting diodes (23a-23h) with a drive voltage, different symbols can be displayed. A user chooses between either a common anode or a common cathode type format depending on the type of voltage available from peripheral devices.

The manufacture of such displays requires that the cavity (12) be filled with liquid epoxy resin (30) first, with the PCB (20) dipped in until its back (22) is covered, then leaving the device to set. Alternatively, the PCB is placed in the cavity (12) first, with the resin (30) then poured in until it covers the back of the PCB (20) and then sets.

Both methods of manufacture produce displays which are quite deep. The cavities (12) have to be deep enough to allow the resin (30) to cover the PCBs (20) and to allow for some variation in the amount of resin (30) used. Moreover, the ten pins (24a - 24j) from the PCBs (20) extend back from the reflector body (10) some distance. Additionally, because the PCBs (20) are fully inserted into the cavities (12), the reflector body (10) have to be longer and wider than the PCB's, with sufficient gaps around each edge of the PCBs (20) to allow the ready flow of the resin (30).

The result is long, wide and deep displays for display segments of a specific size. It also means excessive use of epoxy resin (30) and of moulded plastic in making the reflector body (10). The use of a plurality of such seven-segment displays together in the formation of a larger display means that larger individual reflector bodies increases the overall size of such displays and frustrates miniaturisation.

Additionally, the use of metal pins (24a-24j) adds to the costs and inconvenience. Such pins (24a-24j) have to be force-fitted onto the PCB (20). The reliability of the resultant PCBs is reduced due to production deviations in this process. Unfortunately, the pins (24a-24j) are necessary, because the contacts on the PCBs (20) are otherwise sealed beneath the epoxy resin (30).

One of the principal reasons for the current manufacturing methods for multi- segment displays has been an attempt to reduce the likelihood of air bubbles being left within the epoxy resin that may reside between the light emitting diodes on the front face of the PCB and the resin filled segment holes through which the light is transmitted. Such air bubbles can affect the performance of the multi-segment display.

It is in an attempt to remove the air bubbles that the current production methods rely on immersing the PCB in the epoxy resin to ensure that air bubbles are ' driven out of the epoxy. Naturally, these entirely encase the PCB within the epoxy and leads to the increased size of the components as mentioned previously as well as restricting the manufacture to such displays having protruding pins that may extend from the PCB and through the surrounding epoxy.

The use of pins to act as connections to the multi-segment display makes provision of surface mountable displays more difficult.^" The protruding pins would need to be bent at right angles to allow any form of surface mounting and this may not suit automated processors to fit the multi-segment displays to form larger overall components.

In providing better methods for the expelling of air or the arrangement of epoxy within the reflected body, other design possibilities including units more easily surface mountable may be possible.

OBJECT OF THE INVENTION

The need is present in industry today for cheap, thin, surface-mount displays. The object of the present invention is at least to partially alleviate some of the problems with the known displays and to provide displays that can be thinner and cheaper or at least provide the public with a useful choice.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, there is provided display apparatus comprising: a reflector body having a front face and side walls, with a hollow area behind said front face and surrounded by said side walls, and holes through said front face to said hollow area; circuit board means for fitting onto the back of said reflector body and extending, in at least a first direction, further than the inner surfaces of the side walls of said reflector body are spaced apart in the same at least first direction; and cooperating means for fixing the relative positions of the reflector body and circuit board means; wherein the side walls whose inner surfaces are spaced less far apart than the extent of said circuit board means in the same direction are first side walls; and said circuit board means includes light providing portions and is arranged for providing light towards said holes when the circuit board means is fitted onto the back of said reflector body.

Preferably, the cooperating means comprise: recess means in a front surface of said circuit board means; and protrusion means corresponding to said recess means and extending from the rear of the reflector body. Such protrusion means may extend from tops of first side walls of the reflector body. Said first side walls have length and breadth and said protrusion means should ideally not extend across the full breadth of the tops of the first side walls.

The recess means may even comprise at least two grooves, towards opposite edges of and extending across said front surface of said circuit board means; and said corresponding protrusion means comprise ridges extending along the tops of opposing side walls of the reflector body.

Such grooves may be V-shaped and said ridges inverted- V-shaped.

In the preferred aspect, said side walls include at least two opposing second side walls, being side walls whose inner surfaces are spaced further apart than the extent of the circuit board means in the same direction. Said second side walls may be higher than the first side walls such that, when said circuit board means is fitted onto the back of the reflector body, the rear surface of the circuit board means is substantially flush with the tops of said second side walls and such that, when said circuit board means is fitted onto the back of the reflector body, there is substantially no gap between said second side walls and said circuit board means.

Preferably again, the display is arranged such that, when said circuit board means is fitted onto the back of the reflector body, said circuit board means extends beyond the outer surfaces of said first side walls in said at least first direction. Then, said circuit board means may have contacts for said light providing portions on the portions of the circuit board means which extend beyond the outer surfaces of said first side walls.

Outside said first side walls, said circuit board means suitably extends to be flush with the outer surfaces of the other side walls in a direction perpendicular to said first direction, the circuit board means being "I" shaped.

In the display, the positions of the light providing portions usefully correspond in a one to one relationship with the positions of the holes in the reflector body when the circuit board means is fitted onto the back of said reflector body.

The circuit board means may have at least one first hole therethrough with no corresponding protrusion extending therein when the circuit board means is fitted onto the back of said reflector body.

Said hollow area of said reflector body may include reservoir portions in the back of the front face of said reflector body, said reservoir portions being cavities in the back of said front face which extend towards but do not reach through to the front of said front face.

The apparatus according to one aspect is arranged such that, when the circuit board means is fitted onto the back of said reflector body, the front surface of the circuit board means abuts against said back of the front face of said reflector body.

Said circuit board means is ideally a printed circuit board with light emitting diodes.

Preferably the body has at least seven of said holes through said front face, forming an 8-shape.

The final product further comprises light transmitting resin in said holes through said front face and in the hollow area, between the reflector body and the front surface of said circuit board means, sealing said hollow area and sealing said circuit board means to said reflector body. The resin may also flow into any reservoir portions.

The hollow area and said holes of said reflector body may be dispensed with a fixed amount of said resin before said circuit board means is positioned or said circuit board means may be fitted onto the back of said reflector body and said resin back-dispensed through said at least one first hole into said hollow area and said holes of said reflector body.

The present invention also includes display apparatus comprising an array of a plurality of the above apparatus and includes electronic device including the above apparatus. According to a further aspect, there is provided a method of manufacturing display apparatus, which display apparatus is as defined as above, comprising the steps of: dispensing resin into the holes and said hollow area of a reflector body as defined above; and fitting circuit board means as defined above onto the back of said reflector body.

Said dispensing resin step preferably fills the reflector body to a level no higher than the tops of said side walls and cooperating means.

According to a further aspect again, there is provided a method of manufacturing display apparatus, which display apparatus is as defined above, comprising the steps of: fitting circuit board means as defined above and having at least one first hole as defined above onto the back of a reflector body as defined above; and dispensing resin through said at least one first hole into the hollow area and holes of said reflector body to fill the space defined between the reflector body and the front surface of the circuit board means and to fill said at least one first hole partially.

According to a another aspect, there is provided a method of manufacturing display apparatus comprising the steps of: mounting an array of reflector bodies onto an array of mounting blocks on a base plate with the front faces of the reflector bodies facing outwards; fitting a frame, having apertures therein, over said array of reflector bodies such that the front faces of said reflector bodies, extending through said apertures, are flush with a surface of said frame mounting the frame onto the base plate; applying adhesive sheet to the flush surface of the frame and front faces of the reflector bodies; removing the assembly of adhesive sheet, frame and reflector bodies from the base plate; dispensing resin into the reflector bodies; and fitting circuit board means onto the backs of said reflector bodies.

The step of dispensing resin may be prior to or after the step of fitting circuit board means.

The reflector bodies have side walls and the dispensing resin step ideally fills the reflector bodies to a level no higher than the tops of said side walls.

The above methods may further comprise the steps of: curing the resin, thereby sealing the circuit board means to said reflector bodies; and removing the adhesive sheet and frame from the reflector bodies.

These methods may use the circuit board means and reflector bodies as defined above.

In a yet further aspect, the invention may be said to consist in a display apparatus comprising:

- a reflector body having a front panel and side walls extending substantially transverse to a major plane of said front panel to define a hollow area behind said front panel;

- at least one aperture through said front panel from a front face of said panel to said hollow area;

- a circuit board positioned behind said front panel in or adjacent said hollow area and having at least one light emitter aligned with said aperture through said front panel;

- at least one resin reservoir in a rear face of said front panel for the containment of resin intermediate of the front panel and the circuit board; and

- at least one further reservoir for receiving excess resin upon placement of the curcuit board.

In a yet further aspect in the invention may be said to consist in a method of manufacturing a display apparatus having a reflector body with transversely extending side walls extending from a front panel to define a hollow area behind said front panel and having at least one aperture through said front panel from a front face to said hollow area and a circuit board positioned in or adjacent said hollow area having at least one light emitter positionable to align with said aperture through said front panel comprising the steps of:

- placing a measured quantity of resin within at least one resin reservoir provided in a rear face of said front panel and in said at least one aperture; positioning said circuit board behind said rear face of said front panel to contact said resin; urging said circuit board into a position such that excess resin is urged into a further reservoir positioned behind said front panel of said reflector such that air is expelled from the area between the front panel and the circuit board; and - allowing said resin to harden to hold said circuit board in position.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be further described by way of non-limitative example with reference to the accompanying drawings, in which:-

Figure 1 is a front view of a seven segment display of the prior art.

Figure 2 is a perspective view of the known display of Figure 1;

Figure 3 is a cross-section through the known display of Figure 1 ; Figure 4 shows known internal circuit diagrams for seven segment displays;

Figure 5 is a perspective view of a PCB for use in an embodiment of the invention;

Figure 6 is a cross sectional view of the PCB of Figure 5;

Figure 7 is a perspective view of a reflector body for use in an embodiment of the invention;

Figure 8 is a front view of a display according to an embodiment of the present invention;

Figure 9 is a cross-section through the display of Figure 8;

Figure 10 is a simplified cross-section of a view of a reflector body for use in an embodiment of the invention;

Figure 11 is a cross-section of a reflector body and a PCB before assembly, in accordance with an embodiment of the invention;

Figure 12 is a cross-section of a display according to an embodiment of the present invention;

Figure 13 is a cross-section of a display according to another embodiment of the invention;

Figures 14a - 14f illustrate a method of manufacturing a display, according to another embodiment of the invention;

Figure 15a - 15c illustrate a method of manufacturing a display, according to another embodiment of the invention; and

Figure 16 is a front view of yet another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

An exemplary display of a first embodiment of the invention comprises a surface mount LED display. It has a PCB (50), shown in Figure 5, as its circuit board and a reflector body (70), shown in Figure 7.

In more detail, Figures 5 and 6 show an "I" shaped, rectangular PCB (50), having a front surface (50a) and a rear surface (50b). The PCB (50) has a long dimension in a first direction (along the length of the "I") which is longer than the corresponding length between the inner surfaces of the end walls (78) of a reflector body (70), with which it is to be used. In the short dimension, orthogonal to the first direction, (across the width of the main body of the "I"), the PCB is shorter than the corresponding length between the inner surfaces of the side walls (72) of the reflector body (70).

On the front surface (50a) of the PCB (50), at positions corresponding to the end walls (78) of the corresponding reflector body (70), there is a pair of recesses in the form of V-shaped grooves (61), running the width of the PCB (50).

The PCB (50) has a pair of positioning holes (51) located towards its diagonally opposite corners, passing through from the front to the back. It additionally has four resin holes (52) along its length, again passing through from the front to the back. The positioning holes (51) help to position the PCB (50) on its reflector body (70). The resin holes (52) either allow back filling or escape of resin (as described later).

The PCB (50) has print layouts (54) on the rear side (50b), electrically connected to the front surface (50a) of the PCB, by means of electrically conductive through-holes (53). The front surface (50a) of the PCB (50) has light emitting diodes in their relevant positions. The circuit for the PCB (50) can be a standard one, for instance using the circuit diagrams shown in Figure 4 and mentioned earlier. On the rear surface ends of the PCB (50), along the shorter edges (that is along the top and base of the "I"), exposed print layouts (54) act as contacts to connect the display with its mount and associated peripheral components.

Figure 7 depicts a perspective view of an exemplary reflector body (70) for use with the PCB of Figures 5 and 6. The reflector body (70) has a front face (70a) and four rear side walls (72,78). The back (70b) of the front face and the side walls (72,78) define between them a hollow area.

The two shorter side walls (78) at the ends of the reflector body (70) have protrusions in the form of inverted- V-shaped ridges (73) along their tops. These extend along the length of those side walls, but not completely across their breadths. The point of the ridges (73) is to co-operate with the corresponding grooves (61) on the PCB (50) to fix the relative positions of the PCB (50) and the reflector body (70) during assembly. Additionally, they provide a level above the level of the back (70b) of the front face, to define the hollow area.

The longer side walls (72) along the sides of the reflector body (70) are higher than the shorter side walls (78). In this preferred embodiment they are flush with the back (50b) of the PCB (50), when fitted together.

The reflector body (70) also has a pair of locator pins (71) located on the back (70b) of its front face. Each of these locator pins (71) fits into a corresponding positioning hole (51) on the PCB (50) to position the PCB to the reflector body (70).

The front surface of the reflector body (70a) has seven segment holes (74a-74g) in a "8" shape and a circular hole (74h) in it, as is already known. These extend from the front (70a) to the back (70b) of the front face. The segment holes (74a-74g) are elongate and are longer at the front face (70a) than at the back (70b) of the front face of the reflector body (70). Each of the holes (74a- 74h) respectively corresponds to the position of a light emitting diode (83) on the PCB (50). When the PCB (50) is mounted on the back of the reflector body (70), each of the diodes respectively fits in to the holes (74a-74h).

The back (70b) of the front face of the reflector body (70) has a pair of central reservoirs (77) located on it between the seven segment holes (74a- 74g). Additionally there are side reservoirs (76) on either side, between the segment holes (74a- 74g) and the longer side walls (72).

The assembly of the reflector body (70) and the PCB (50) is permanently set by affixing them with a resin, in the form of a combined resin hardener epoxy. A finished assembly is shown from the front in Figure 8, with the resin filled segment holes forming reflector segments (83a-83h). A cross-section through Figure 8 along line A-A is shown in Fig 9.

An exemplary manufacturing method is now described with reference to Figures 10 to

12.

According to this method, the holes (74a-74h) in the front face (70a) and the hollow area of the reflector body (70), which includes the reservoirs (77), are filled with a molten resin/hardener epoxy (85). The PCB (50) is then placed on the back of the reflector body (70) and properly positioned, such that the ridges (73) on the short side walls (78) protrude into the grooves (61) in the PCB (50) and the locator pins (71) fit into the corresponding positioning holes (51) in the PCB (50). The front (50a) of the PCB (50) also rests against the back (70b) of the front face of the reflector body (70). The PCB (50) is held in position by the resin in the holes (74a-74h) in the front face (70a) and in the reservoirs (77). Excess resin from the hollow area is forced up the resin holes (52), as shown in Figure 9 to form minisci (171) within resin holes (52), before hardening. Excess resin is also urged into the side reservoirs (76)

The ends of the PCB (50) extend over the end side walls (78). These extending portions also extend outwards in an orthogonal direction. However, they do not extend beyond the outer surfaces of the longer side walls (72). Thus they are flush with those walls (72). The back surface (50b) of the PCB (50) is also flush with the tops of the longer side walls (72). The side edges of the PCB (50) also contact the longer side walls (72) along their lengths, preventing any leakage of resin. Thus the whole package is neat, shallow and rectangular.

The quantity of the resin is limited or fixed such that it does not go above the level of the tops of the ridges (73). In this way, the excess is limited such that it does not flow through the resin holes (52) onto the top (50b) of the PCB (50) or out over the ends of the reflector body (70). This maintains the tidy, flat backed and rectangular aspect of the display.

Figure 13 shows a display produced according to a second method. The reflector body (70) and the PCB (50) are as illustrated and described before. However, the PCB (50) is positioned on the reflector body (70) before the resin is introduced into the reflector body (70). Once it is correctly positioned as described before, resin (85) is back-dispensed through the resin holes (52), from the back surface (50b) of the PCB (50).

Again the amount of resin is limited, so that the resin fills the holes (74a-74h) in the front face (70a) with excess resin absorbed into the reservoirs (76), forming minisci (211) within the rear (70b) of the front faces of the display bodies (70). Some resin also stays in the resin holes (52).

Further details of these described methods are now described. The first description is for the resin dispensed into the reflector body (70) before the PCB (50) is fitted.

As shown in Figures 14a and 14b, an array of reflector bodies (70) is clipped onto an array of mounting blocks (91) on a base plate (92) such that the front, light emitting surface (70a) of each reflector body (70) faces upwards. Subsequently (as shown in Figure 14c) a steel frame (111) is fitted over the array of reflector bodies (70) and is mounted to the base plate (92) using mounting pins (112). The steel frame (111) has an array of apertures, which receives the corresponding array of reflector bodies (70), such that the light emitting surface (70a) of each Teflector body (70) becomes flush with the top surface of the frame (111).

Subsequently (as shown in Figure 14d), an adhesive sheet (113) is applied to the flush top surfaces of the steel frame (111) and the array of reflector bodies (70). The sheet is tape like for single arrays or more sheet like for arrays in two dimensions. The purpose of applying the adhesive sheet (113) is to ensure that the front surface of the array of reflector body (70) is kept flat and together. The mounting pins (112) and the base plate (92) are then removed from the assembly of adhesive sheet (113), steel frame (111) and reflector bodies (70).

This assembly is then inverted to a position shown in Figure 14e, whereby the adhesive sheet (113) is underneath the frame (111) and reflector bodies (70). The hollow surfaces of the reflector bodies (70) face upwards.

A combined resin/hardener epoxy (85), from a weight controlled epoxy container (131) is then dispensed through nozzles (132) into the hollow areas of reflector bodies (70) at room temperature.

Following this, Figure 14f shows an array of PCBs (50) fitted on to the backs of the reflector bodies (70). The resin (85) permanently sets the reflector bodies (70) and PCBs (50) together. After hardening, the adhesive sheet (113) is removed from the front faces (70a) of the array of reflectors, resulting in a finished product.

The second method is also further described, with reference to Figures 15a to 15c. The first four steps are the same as the previous manufacturing method, as shown and described above with reference Figures 14a to 14d, to the point where the assembly of steel frame (111), adhesive sheet (113) and reflector bodies (70) are inverted to have the adhesive sheet (113) underneath (Figure 15a). At that stage, instead of dispensing resin into the reflector bodies (70), Figure 15b shows the array of PCBs (50) is fitted onto the reflector bodies (70).

Subsequently (as shown in figure 15c) a weight-controlled epoxy dispenser (131) back-dispenses a fixed quantity of resin hardener (85) via nozzles (132) located on the dispenser (131) through the epoxy holes (52). The weight of the dispensed epoxy (85) is so defined that excess epoxy is absorbed into the reservoirs (76), forming minisci (211) within the rear (70b) of the front faces of the display bodies (70).

The surface mount light emitting displays as manufactured in accordance with the above embodiments can be utilized in a variety of electronic devices. The compactness of the displays makes it more suitable for use in thin or multi-stacked displays.

The invention is not limited to the above-mentioned embodiments only. Variations are possible. For example, the pair of ridges located on the end side walls of the reflector body may instead be located on the longer side walls and the recesses on the PCB may correspondingly be located towards the longer edges of the PCB. In this way the excess PCB and the contacts would extend over the sides, rather than the ends. Such a display is shown in Figure 16, which would be useful for vertically stacked displays.

Alternatively, the protrusions and recess cooperating means may need to be at only one end side or side side, all ends and sides, or any combination of ends and sides as may be required, with the contacts extending outside the reflector body from one, two, three or four sides accordingly. The display need not be rectangular (or square), it may be irregularly shaped, polygonal (e.g. triangular), circular or almost any shape. Further, other cooperating means are possible, e.g. which do not extend along the entire lengths of the sides, which use pins and holes or which use other means. IS

The sides over which the PCB does not extend are preferably flush with the back of the PCB. Again, that is not necessary. The back of the PCB could be higher or lower.

The PCB is described above as sitting on the back of the front face. That may be changed to have a gap therebetween, though preferably only a small one, for instance of only the height of a LED on the PCB. This allows flow of the resin, especially when it is back-dispensed.

The displays have been exemplified as seven segment displays. However, the invention is not so limited. It may have any number of holes in the front face, from one upwards or more than one upwards, in whatever shape and pattern desired to produce whatever display wanted, e.g. to produce Roman, Greek, Cyrillic or Arabic letters etc or Japanese or Chinese characters etc.

The PCB is described as having light emitting diodes. Other means of providing light are equally applicable, e.g. by heat emission, by laser, by the reaction of components (such a phosphorous) of the resin (or other filler) with emitted electrons or by other means. Indeed the invention is also not limited to the spectrum visible to the naked human eye. It can be used to provide displays which can only be discerned in other EMR spectra.

Additionally the light providing means does not have to be on a PCB. Other circuit board means are equally usable, including those that are essentially chemical or biological.

The exemplary methods illustrate arrays of five reflector bodies. Of course the array may consist of any number of reflector bodies arranged in rows and/or columns or arranged otherwise.

The PCB may be modified to have mounting metallic pins for manual insertion instead of SMT. The resin may be side-dispensed through holes in the reflector body sides. The numbers of positioning holes on the PCB and locator pins in the reflector body can be varied. Similarly, the number of resin holes can be varied. However, at least two is preferred, to reduce problems with air bubbles.

In alternative embodiments of the present invention, it will be appreciated that aspects of this invention may be taken without the entire solution as described in the preferred embodiment.

As shown in the preferred embodiment, the apparatus uses different mechanisms to endeavour to ensure that there are no air bubbles in the epoxy between the LEDs and the front face of the reflected body without totally immersing the PCB. During manufacture, the epoxy is placed in the body of the reflector principally in the central wells 77 and within the holes (74 a-h). This is done with a controlled amount of resin slightly greater than that necessary to completely fill the space between the reflected body and the PCB. While the PCB is fitted, excess resin is forced into the side reservoir 76 as well as through the apertures 52 in the PCB so as to allow overfill of the areas requiring epoxy such as directly underneath the PCB and the LED yet allowing for overflow without covering the back of the PCB itself.

Such aspects of the invention can be incorporated without the PCB overlapping opposed sides of the reflector and without the co-operating grooves and protrusions on abutting edges as is provided in the preferred embodiment. The overlapping PCB does make availability of connection points for surface mounting significantly easier, however, these additional aspects of the invention concerning the expelling of air can be incorporated to still provide a smaller low profile reflector without the overlapping portions of the PCB. The PCB could still be nested within all four side walls of a reflector or indeed provided simply flush with the back face of a reflector.

As location of the PCB is important given the minimal excess resin applied within the reflected body, the located pins 71 can be used or other locators such as stands from the PCB itself or location simply on portions of the edge of the reflected body can be provided.

Although the preferred embodiment is sought to provide a surface mountable multi-segment display and provides an overlapping PCB, a smaller more compact multi-segment display than those previously known can be provided utilizing the excess resin reservoirs provided in the reflected body while pins may still be used as connection points from the PCB itself in a traditional method.

While the invention has been described in terms of the above embodiments and variations, it is apparent that other forms may be adopted by one of those skilled in the art within the scope of the present invention.

Claims

1. Display apparatus comprising: a reflector body having a front face and side walls, with a hollow area behind said front face and surrounded by said side walls, and holes through said front face to said hollow area; circuit board means for fitting onto the back of said reflector body and extending, in at least a first direction, further than the inner surfaces of the side walls of said reflector body are spaced apart in the same at least first direction; and cooperating means for fixing the relative positions of the reflector body and circuit board means; wherein the side walls whose inner surfaces are spaced less far apart than the extent of said circuit board means in the same direction are first side walls; and said circuit board means includes light providing portions and is arranged for providing light towards said holes when the circuit board means is fitted onto the back of said reflector body.

2 Apparatus according to claim 1, wherein the cooperating means comprise: recess means in a front surface of said circuit board means; and protrusion means corresponding to said recess means and extending from the rear of the reflector body.

3 Apparatus according to claim 2, wherein said protrusion means extend from tops of first side walls of the reflector body.

4 Apparatus according to claim 3, wherein said first side walls have length and breadth and said protrusion means do not extend across the full breadth of the tops of the first side walls.

5 Apparatus according to claim 3 or 4, wherein the recess means comprise at least two grooves, towards opposite edges of and extending across said front surface of said circuit board means; and said corresponding protrusion means comprise ridges extending along the tops of opposing side walls of the reflector body.

6 Apparatus according to claim 5, wherein said grooves are V-shaped and said ridges are inverted- V-shaped.

7 Apparatus according to any one of claims 3 to 6, wherein said reflector body is elongate and said protrusion means are provided on first side walls at opposite ends of said reflector body.

8 Apparatus according to any one of the preceding claims, wherein said side walls include at least two opposing second side walls, being side walls whose inner surfaces are spaced further apart than the extent of the circuit board means in the same direction.

9 Apparatus according to claim 8, wherein said second side walls are higher than the first side walls.

10 Apparatus according to claim 9, arranged such that, when said circuit board means is fitted onto the back of the reflector body, the rear surface of the circuit board means is substantially flush with the tops of said second side walls.

11 Apparatus according to claim 8, 9 or 10, arranged such that, when said circuit board means is fitted onto the back of the reflector body, there is substantially no gap between said second side walls and said circuit board means.

12 Apparatus according to any one of the preceding claims, arranged such that, when said circuit board means is fitted onto the back of the reflector body, said circuit board means extends beyond the outer surfaces of said first side walls in said at least first direction. 13 Apparatus according to claim 12, wherein said circuit board means has contacts for said light providing portions on the portions of the circuit board means which extend beyond the outer surfaces of said first side walls.

14 Apparatus according to claim 12 or 13, wherein, outside said first side walls, said circuit board means extends to be flush with the outer surfaces of the other side walls in a direction perpendicular to said first direction.

15 Apparatus according to any one of the preceding claims, wherein said side walls of said reflector body form a rectangle.

16 Apparatus according to claim 15 when dependent on claim 13 or 14, wherein said circuit board means is I-shaped.

17 Apparatus according to any one of the preceding claims, wherein said reflector body further comprises locating pins extending rearwardly from the back of said front face; and said circuit board means further comprises holes therein corresponding to said locating pins.

18 Apparatus according to claim 17, wherein said locating pins are positioned towards diagonally opposite corners of said back of said front face.

19 Apparatus according to any one of the preceding claims, arranged such that the positions of the light providing portions correspond in a one to one relationship with the positions of the holes in the reflector body when the circuit board means is fitted onto the back of said reflector body.

20 Apparatus according to any one of the preceding claims, wherein the circuit board means has at least one first hole therethrough with no corresponding protrusion extending therein when the circuit board means is fitted onto the back of said reflector body.

21 Apparatus according to any one of the preceding claims, wherein said hollow area of said reflector body includes reservoir portions in the back of the front face of said reflector body, said reservoir portions being holes in the back of said front face which extend towards but do not reach through to the front of said front face.

22 Apparatus according to any one of the preceding claims, arranged such that, when the circuit board means is fitted onto the back of said reflector body, the front surface of the circuit board means abuts against said back of the front face of said reflector body.

23 Apparatus according to any one of the preceding claims, wherein said circuit board means is a printed circuit board.

24 Apparatus according to any one of the preceding claims, wherein said light providing portions are light emitting diodes.

25 Apparatus according to any one of the preceding claims, having at least seven of said holes through said front face forming an 8-shape.

26 Apparatus according to any one of the preceding claims further comprising light transmitting resin in said holes through said front face and in the hollow area, between the reflector body and the front surface of said circuit board means, sealing said hollow area and sealing said circuit board means to said reflector body.

27 Apparatus according to claim 26 when dependent on at least claim 21, wherein said resin is also in said reservoir portions.

28 Apparatus according to claim 26 or 27, when dependent on at least claim 20, wherein said resin is also in said at least one first hole in said circuit board means.

29 Apparatus according to any one of claims 26 to 28 when dependent on at least claim 24, being a surface mount light emitting diode display.

30 Apparatus according to any one of claims 26 to 29, wherein the hollow area and said holes of said reflector body are dispensed with a fixed amount of said resin before said circuit board means is positioned.

31 Apparatus according to any one of claims 26 to 29 when dependent on at least claim 20, wherein said circuit board means is fitted onto the back of said reflector body and said resin is back-dispensed through said at least one first hole into said , hollow area and said holes of said reflector body.

32 Display apparatus comprising an array of a plurality of apparatus, each according to any one of the preceding claims.

33 An electronic device comprising display apparatus according to any one of the preceding claims.

34 A method of manufacturing display apparatus, which display apparatus is as defined in any one of claims 1 to 30, comprising the steps of: dispensing resin into the holes and said hollow area of a reflector body as defined in any one of claims 1 to 25; and fitting circuit board means as defined in any one of claims 1 to 25 onto the back of said reflector body.

35 A method according to claim 34, wherein said dispensing resin step fills the reflector body to a level no higher than the tops of said side walls and cooperating means. 36 A method according to claim 34 or 35, wherein the circuit board means has at least one first hole as defined in claim 20; and said fitting step causes excess resin in the hollow area of said reflector body to flow up into said at least one first hole.

37 A method of manufacturing display apparatus, which display apparatus is as defined in any one of claims 1 to 29 and 31, comprising the steps of: fitting circuit board means as defined in any one of claims 1 to 25 and having at least one first hole as defined in claim 20 onto the back of a reflector body as defined in any one of claims 1 to 25; and dispensing resin through said at least one first hole into the hollow area and holes of said reflector body to fill the space defined between the reflector body and the front surface of the circuit board means and to fill said at least one first hole partially.

38 A method of manufacturing display apparatus comprising the steps of: mounting an array of reflector bodies onto an array of mounting blocks on a base plate with the front faces of the reflector bodies facing outwards; fitting a frame, having apertures therein, over said array of reflector bodies such that the front faces of said reflector bodies, extending through said apertures, are flush with a surface of said frame mounting the frame onto the base plate; applying adhesive sheet to the flush surface of the frame and front faces of the reflector bodies; removing the assembly of adhesive sheet, frame and reflector bodies from the base plate; dispensing resin into the reflector bodies; and fitting circuit board means onto the backs of said reflector bodies.

9 A method according to claim 38, wherein the step of dispensing resin is prior o the step of fitting circuit board means. 40 A method according to claim 39, wherein the reflector bodies have side walls and the dispensing resin step fills the reflector bodies to a level no higher than the tops of said side walls.

41 A method according to claim 38, wherein the step of fitting circuit board means is prior to the step of dispensing resin and the resin is dispensed into said reflector bodies through holes in the backs of the circuit board means.

42 A method according to any one of claims 38 to 41, wherein the step of fitting circuit board means comprises fitting individual separate circuit board means onto the backs of said reflector bodies.

43 A method according to any one of claims 38 to 42, wherein the dispensing resin step comprises dispensing controlled amounts of said resin into said reflector bodies.

44 A method according to any one of claims 38 to 43, further comprising the steps of: curing the resin, thereby sealing the circuit board means to said reflector bodies; and removing the adhesive sheet and frame from the reflector bodies.

45 A method according to any one of claims 38 to 44, wherein the reflector bodies and circuit board means are as defined in any one of claims 1 to 25.

46 A method according to any one of claims 38 to 44, being a method of manufacturing display apparatus according to any one of claims 26 to 31.

47 Display apparatus comprising an array of a plurality of apparatus, each manufactured according to the method of any one of claims 34 to 46. 48 An electronic device comprising display apparatus manufactured according to the method of any one of claims 34 to 46.

49 A method of manufacturing display apparatus substantially as hereinbefore described with reference to and as illustrated in accompanying Figures 5 to 16.

50 Display apparatus constructed and arranged substantially as hereinbefore described with reference to and as illustrated in accompanying Figures 5 to 16.

51 A display apparatus comprising:

- at least one aperture through said front panel from a front face of said panel to said hollow area; a circuit board positioned behind said front panel in or adjacent said hollow area and having at least one light emitter aligned with said aperture through said front panel;

A display apparatus as claimed in Claim-51 wherein said resin reservoir is postioned intermediate of the side walls of the reflector body.

A display apparatus as claimed in Claim 52 wherein said at least one further reservoir is postioned adjacent a side wall of said reflector body. A display apparatus as claimed in claim 51 wherein at least one aperture is provided in the circuit board to indicate the level of resin beneath the circuit board upon placement.

A display apparatus as claimed in claim 51 wherein said circuit board abuts and extends beyond an opposed pair of side walls of said reflector body.

A display apparatus as claimed in claim 55 wherein conductible connection points for said circuit board are provided on portions extending beyond said side walls of said reflector body to provide for surface mounting of said display.

A method of manufacturing a display apparatus having a reflector body with transversely extending side walls extending from a front panel to define a hollow area behind said front panel and having at least one aperture through said front panel from a front face to said hollow area and a circuit board positioned in or adjacent said hollow area having at least one light emitter positionable to align with said aperture through said front panel comprising the steps of:

- placing a measured quantity of resin within at least one resin reservoir provided in a rear face of said front panel and in said at least one aperture;

- positioning said circuit board behind said rear face of said front panel to contact said resin;

- urging said circuit board into a position such that excess resin is urged into a further reservoir positioned behind said front panel of said reflector such that air is expelled from the area between the front panel and the circuit board; and

- allowing said resin to harden to hold said circuit board in position. A method as claimed in Claim 57 wherein said circuit board contains at least one aperture and the circuit board is urged against the reflector body until a menisci of resin is formed within said aperture.

A method as claimed in Claim 57 wherein said steps are performed by an automated production apparatus.