JPH0545074B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an LED array light source in which LEDs (light emitting diodes) are arranged in a row at a fine pitch, and in particular, for example, a line light source for an eraser in a copying machine, etc. The present invention relates to an LED array light source suitable for use in.

[Prior art and its problems]

In recent years, as office equipment such as copiers and printers have become smaller and more intelligent, the application of line light sources that use compact, long-life LEDs as light sources has expanded.

In particular, high-end copying machines have appeared that image-process and copy only the necessary parts of newspapers, etc., leaving the rest as blank space.
There will be a mixture of light-emitting parts and non-light-emitting parts.
For this reason, instead of conventional fluorescent lamps, LEDs have been used to create compact line light sources that consume less power, have higher illuminance, and are capable of partial exposure.

This type of conventional LED array as a line light source consists of bonding LED chips on the stem.
In addition, a light-emitting element component consisting of a lens fixed on a stem to cover the LED chip was used, and this light-emitting element component was arranged and planted within each partition frame, making it possible to reduce the size of the LED chip. If so, there was a certain limit to the selective light emission of minute pitches.

Therefore, the applicant of the present application attempted to miniaturize the light source pitch of a line light source by attaching LED chips directly to a printed circuit board, for example, and also to connect each LED chip and each corresponding lens at the bottom using synthetic resin. One-piece molding was proposed in Japanese Patent Application No. 194749/1984 (Japanese Patent Application No. 55973/1983). The configuration of this prior application is shown in FIG. 9 and will be described below.

In FIG. 9, 51 is a printed circuit board made of ceramics or the like, 52 is LED chips arranged in a row on the printed circuit board 51, and their cathodes and anodes are bonded to a conductive pattern (not shown) on the printed circuit board 51. In the prior application shown in FIG. 9, the pitch between the LED chips 52 is about 2.5 mm. 53 is a partition frame,
A rectangular small chamber 54 that accommodates each LED chip 52
have. This partition frame 53 is integrally molded from black or other light-absorbing synthetic resin, and its height is kept as low as possible within the range allowed by the dimensional accuracy and strength of the molding (manufacturing considering mass production). Its height is said to be approximately 1 mm.

Reference numeral 55 denotes a transparent acrylic lens (plano-convex lens), which is integrally molded so as to be connected to adjacent lenses in a row through a connecting portion 55a, and each lens is placed in the small chamber 54. And the small room 5
Since the inner wall of the LED chip 52 has a light-absorbing structure, only the direct incident light from the LED chip 52 is guided to the lower surface of the lens 55, and the incident light to this lens 55 is, for example, 4 mm from the top of the lens 55. The light is refracted by the lens 55 so that a certain unit target area 56 is irradiated with a substantially uniform amount of light. Incidentally, in FIG. 9, the overall height of the lens 55 is 1.4 mm, and the height (thickness) of the connecting portion 55a is 1.4 mm.
S ₁ is said to be 0.5mm.

The configuration shown in FIG. 9 described above can achieve a certain degree of miniaturization of the arrangement pitch of the LEDs, and since the lens 55 is integrally molded, it is suitable for mass production and easy to assemble. However, since the lenses 55 are connected by the connecting portion 55a, if the arrangement pitch is made even finer, the width of each lens will also become smaller, and therefore the relative height of the connecting portion 55a will be reduced. It will increase. This will be explained using FIG. 9. When the width of each lens becomes smaller as shown by the two-dot chain line on the left side of Figure 9,
This indicates that the height of the connecting portion 55a increases relatively. In this situation, as shown in the figure
The incident light from the LED chip 52 is transmitted and leaked to the area of the adjacent lens 55, and the adjacent LED
The chip also acts as if it were emitting light, making the LED chip light source less crisp when selectively emitting light. Furthermore, when light leaks to adjacent lenses in this way, it affects the brightness of the adjacent LED chips themselves, causing variations in the illuminance in each unit target area 56, which is a fatal defect. do. For this reason, it is desirable to reduce the height of the connecting portion 55a at least to the extent that light does not leak to adjacent lenses. However, in order to do this, the lens shape must be changed, which means
This hinders the degree of freedom in lens design. Furthermore, if the connecting portion 55a is made smaller, it becomes locally extremely thin, making the connecting portion 55a more likely to break, degrading the mechanical strength of the lens system and making molding difficult.

If the height of the partition frame 53 is increased in order to avoid the above-mentioned problem in the connecting portion 55a, the angle of elevation seen from the LED chip 52 will be reduced and light leakage will be eliminated.
It reaches the lower surface of the lens 55 as the elevation angle decreases.
The total amount of light from the LED chip 52 decreases, resulting in a decrease in brightness, which is undesirable.

Furthermore, the arrangement pitch of the LED chips 52 is
For example, if the pitch is further reduced to 1 mm, the overall height of the lens 55 will be 1 mm as shown in FIG.
If it becomes this thin, it will be difficult to achieve precision in lens shape when integrally molding the lens 55 group, making it difficult to manufacture from a mass production standpoint. The drawback that close assembly onto the frame 53 would cause damage was noticeable.

[Purpose of the invention]

Therefore, the technical problem to be solved by the present invention is to eliminate the above-mentioned conventional drawbacks.
The light emitted by the LED must not leak to adjacent lenses other than the corresponding lens, and the lens must have sufficient mechanical strength so that there is no risk of damage during assembly, and it must be integrally molded to be suitable for mass production. As a possible lens structure, it is easy to align the lens and the partition frame, and the light entrance surface of the lens is
An object of the present invention is to provide an LED array light source having a structure that can be placed close to LEDs.

[Means to solve problems]

The above-mentioned object of the present invention is to provide a plurality of LEDs disposed on a substrate and a plurality of lenses each having a convex or planar light incident surface on the lower surface, arranged spaced apart from each other, and arranged on a side surface different from an adjacent surface. It includes a lens complex made of a translucent synthetic resin integrally with a base, and a partition frame formed by arranging a plurality of small chambers with openings at both ends, and the plurality of LEDs are arranged so that the substrate is The lens complex is arranged in each of the small chambers by being arranged in the partition frame from the opening side of one end of the small chamber, and the lens complex is arranged such that the base thereof is different from the side of the partition frame on which the substrate is arranged. The plurality of lenses are placed on different sides, and each of the plurality of lenses is arranged on an opening side of each of the small chambers that is different from the side on which the plurality of LEDs are arranged, and the inner wall of each of the small chambers of the partition frame is separated from each of the LEDs. It is characterized by having a light-absorbing structure that allows only the directly incident light to enter each lens and absorbs other light from the LED.
This is achieved by using an LED array light source.

According to a preferred embodiment of the present invention, the side surface of each lens adjacent to the adjacent lens is an inclined surface such that the light entrance surface of the lower surface is smaller than the exit surface of the upper surface.

Further, according to a preferred embodiment of the present invention, a predetermined amount of the lens is placed in the small chamber so that a part of the side surface of each lens adjacent to the adjacent lens comes into contact with the upper edge of the opening of the small chamber of the partition frame. inserted.

Further, according to a preferred embodiment of the present invention, each lens in the lens complex corresponds to every other LED in the group of LEDs arranged in the row,
By interlocking the two lens complexes, the lenses can be arranged to correspond to all of the LED groups of a certain length.

[Effect]

In the lens complex, each lens is spaced apart from each other and adjacent surfaces of adjacent lenses are separated, so that light emitted from each LED does not enter adjacent lenses. In addition, in the lens complex, each lens is integrally connected to the base at the side surface corresponding to the lens width, so a thickness corresponding to the lens width can be secured and sufficient mechanical strength can be achieved. The positional accuracy is ensured by this base.

By interlocking two lens complexes,
The mechanical strength is further improved without light leakage, and the positional accuracy is further improved, and furthermore, the mechanical strength and positional accuracy are guaranteed as much as possible,
Furthermore, the pitch width can be reduced.

〔Example〕

The present invention will be explained below with reference to illustrated embodiments.

1 to 4 relate to one embodiment of the present invention, FIG. 1A is an exploded perspective view showing a lens complex and a partition frame, and FIG. 1B is a main part showing an LED chip on a printed circuit board. FIG. 2 is a perspective view, FIG. 2 is a sectional front view of the main part, FIG. 3 is a plan view of the main part, and FIG. 4 is an explanatory diagram showing the optical path.

In the figure, reference numeral 1 denotes a printed circuit board, and although a ceramic substrate is used in this embodiment, it may be made of an appropriate material such as a glass epoxy substrate, a polyimide substrate, a metal substrate with an insulating coating, or a flexible substrate. A large number of LED chips 2 as light emitting sources are arranged in a row on the printed circuit board 1 at equal intervals. the above
The LED chips 2 are connected to the conductive patterns 3 and 4 on the printed circuit board 1 by known die bonding and wire bonding, and in this embodiment, the arrangement pitch of each LED chip is set to 1 mm, which is 0.3 mm. The direction in which the wire 5 is drawn out from the anode of the LED chip 2, which is approximately mm square, is
It is perpendicular to the row of two groups of LEDs.

Reference numeral 6 denotes a substantially rectangular thin plate partition frame made of a light-absorbing synthetic resin that has excellent insulation properties and molding dimensional stability, and is made of black polybutylene terephthalate in this embodiment. A number of small chambers 7 corresponding to the number of the chambers 7 are each formed with openings at both ends thereof. [For convenience of illustration, the partition frame 6 and the comb-like lens complex described later are shown shorter than they actually are, and the partition frame 6 actually has 300 or more small chambers formed integrally. It is considered to be the length. Also,
The number of comb teeth (lenses) in the comb-tooth lens complex was actually 50 or more, and two paired lens complexes were combined as described below. Multiple items will actually be used. In addition, it is also possible to use a combination of multiple partition frames 6, and these are LED
It is set depending on the overall array length of the chip group and the molding conditions. ] In this embodiment, the thickness of the partition frame 6 is 1 mm, and each rectangular small chamber 7 has a vertical direction on the top side in the figure.
The horizontal dimensions are 3.2 mm x 0.8 mm, and the arrangement pitch of each small chamber 7 is 1, which is equal to the arrangement pitch of LED chips 2.
It is set to mm. Further, the vertical inner wall of each small chamber 7 is an inclined surface as shown in the second figure. Note that 8 is a small shaft formed integrally with the partition frame 6, and is inserted into a positioning hole of the lens complex described later. Further, reference numeral 9 denotes a mounting hole drilled in the partition frame 6.

Reference numeral 10 denotes a comb-shaped lens composite integrally formed from transparent acrylic resin or the like, and includes a lens 11 made of each comb-teeth and a flat plate-shaped base 12 integrally connected to the lens 11. The arrangement pitch of the lenses 11 is 2 mm, which is twice the arrangement pitch of the LED chips 2, and corresponds to every other LED chip 2 in the 2 groups of LED chips. The height (thickness) H ₁ of the base 12 and the height of the lens 11 which is approximately the same height as this
_H2 is set to a value higher than a predetermined value to guarantee mechanical strength, and in this example, _H1 is 2.5mm and _H2 is
It is said to be 2.68mm. As a result, each lens 11 can be guaranteed sufficient mechanical strength, and each lens 11
Since the lenses are separated from each other at the adjacent lenses and their adjacent side surfaces, it becomes easy to achieve precision in the outer shape of each lens during the molding process. The cross-sectional shape of the lens 11 (FIG. 2) can be arbitrarily selected depending on the lens design, and in this example, it is a vertically long biconvex lens with convex upper and lower surfaces,
As shown in the figure, the area of each lens 11 (relative to the adjacent lens) is adjusted so that the area of the lower surface 11b, which is the light entrance surface, is smaller than the upper surface 11a, which is the exit surface.
The side surface 11c is an inclined surface.

As mentioned above, tapering the side surface 11c of the lens 11 improves the "removal property" between the mold and the product during molding.
will improve. Moreover, this taper facilitates positioning during the mating process of the pair of lens composite bodies 10 and the assembly process of the lens composite body 10 and the partition frame 6, which will be described later. Incidentally, in this embodiment, the upper surface 11a of the lens 11
The plane vertical and horizontal dimensions of are 2.8 mm x 1.0 mm, those of the lower surface 11b are 2.8 mm x 0.8 mm, and the side surface 11c is gently tapered.

Two lens complexes 10 that form a mating pair
are of the same shape as shown in FIG. 1A (this becomes clear when rotated 180 degrees in a plane in FIG. 1A), and the positioning hole 13 into which the small shaft 8 of the partition frame 6 fits is used. and a mounting hole 14 facing the mounting hole 9 are provided. The positioning hole 13 has a small diameter portion 1 in which the small shaft 8 matches and fits.
3a and a wide diameter portion 13b connected to these, and after the small shaft 8 is inserted into the positioning hole 13, the top thereof is heat caulked within the wide diameter portion 13b. ing.

That is, when assembling, the lens complex 10 on one side is first placed on the partition frame 6, the small shaft 8 of the partition frame 6 is fitted into the positioning hole 13 of the lens complex 10, and the lens complex 10 is placed on the partition frame 6. 10 each lens 1
The lower surface 11b of 1 of the 7 groups of small rooms of the partition frame 6
It is fitted into the upper part of the small chamber 7 of the tsuoki. In this state, each lens 11 of the other lens complex 10 is
It is placed on the partition frame 6 so as to mesh with each lens 11 of the lens complex 10 placed on the partition frame 6, and similarly, the small shaft 8 is fitted into the positioning hole 13, and The lower surface of each lens 11 of the lens complex 10 placed later is fitted into the upper part of every other remaining small chamber 7. (In addition, 2
The partition frame 6 has two lens complexes 10 interlocked with each other.
Alternatively, if there are a large number of lens complexes 10, they will be sequentially assembled to the partition frame 6. ) After positioning and combining the lens complex 10 and the partition frame 6 as described above, the small shaft 8 is thermally caulked as described above, and the lens complex 10 and the partition frame 6 are combined into an integrated sub-shaft. It is considered an assembly product. After that, this subassembly product is aligned with the printed circuit board 1 and the LED chips 2 are positioned in each small chamber 7, and the printed circuit board 1, the partition frame 6, and the lens complex 10 are assembled. are integrated by mounting screws (not shown) inserted through the mounting holes 9, 14 (the mounting holes of the printed circuit board are not shown). (Incidentally, a mounting plate may be provided on the bottom surface of the printed circuit board 1 and integrated with this.) The second section shows a cross section of the main part in this assembled state.
In the figure, each lens 11 of the two lens complexes 10, 10 (in the figure, one is shown by hatching downward to the right and the other downward to the left) combined as shown in FIG. The upper edges of each lens 11 are in line contact with the adjacent lenses, and the lower edges of each lens 11 are fitted into the upper part of the inner wall of the small chamber 7. Then, like this, the adjacent lens 1
When the lenses 11 are in line contact with each other, it is possible to eliminate adverse optical effects at this portion due to contact deformation of the lens 11. Further, if the contact portion between adjacent lenses is as small as possible, when the incident light is forwardly reflected at the side surface 11c of each lens 11, transmission of light to the adjacent lens 11 can be completely eliminated.

The LED array light source assembled in this way is
Since each lens 11 has an elongated rectangular shape when viewed from the top surface, the top surface (light exit surface) 1 of each lens 11
In order to make 1a a nearly square light exit surface, for example, a black adhesive tape 1 is used as shown in the third figure.
5 is attached so as to cover both vertically long end portions of the lens 11 group.

FIG. 4 shows the optical path of the lens 11 in the embodiment described above. As mentioned above, the partition frame 6 has a light-absorbing structure, so when modeled, only the directly incident light from the LED chip 2 enters the lower surface 11b of the lens 11, and this directly incident light enters the convex part of the lens 11. It is refracted by the lower surface 11b of the lens 11 to become a slightly outwardly expanding, substantially parallel light, and then refracted by the convex upper surface 11a of the lens 11 to become a slightly convex, substantially parallel light to the target area 1.
6 is irradiated with a substantially uniform amount of light.
In this case, the focal point of the convex lens on the upper surface 11a of the lens 11 is located further away than the target area 16, which is about 4 mm from the top of the lens 11, but the distance to the target 16 and the diffusion of light based on this The focal point position can be set arbitrarily, taking into consideration the following.

Further, the optical design of the lens 11 can be modified in various ways other than the above-mentioned embodiments. For example, as shown in FIG. The light may be refracted at 17a so as to irradiate the target area 16 substantially uniformly. In the embodiment shown in FIG. 5, a portion of the directly incident light from the LED chip 2 is totally reflected by the side surface 17c of the lens 17. The upper surface 17a of the lens 17 has a shape in which the top of a convex lens is flattened, and the central flat portion 17a-1 of the upper surface 17a is
It is provided with a function to average the amount of irradiation light in the target area 16.

Further, as shown in FIG. 6, the lower surface 18 of the lens 18
b may be a convex lens, and the upper surface 18a may be a flat light exit surface. In this case, the light incident on the lens 18 is converted into parallel light inside the lens 18, and the target area 16 is irradiated as this parallel light. Become. In the example shown in FIG. 6, the lens 18 is inserted a predetermined amount into the partition frame 6' so that the side surface of the lens 18 is in line contact with the inner wall edge of the partition frame 6'. By doing this, the lower surface 18b of the lens 18 can be brought closer to the LED chip 2, and therefore the incident light angle α from the LED chip 2 can be increased, and the illuminance can be increased.

In addition to this, the optical design of the lens can be freely changed depending on the material and requirements.Depending on the material, there are also pseudo-self-cleaning lenses whose upper and lower surfaces (light entrance/exit surfaces) are approximately flat. In some cases, it may be possible to do so. Furthermore, when the two lens complexes 10, 10 are meshed together, the adjacent lenses 11 are brought into line contact as described above, but a slight gap may be provided between the meshed adjacent lenses; in this case, There is no problem even if the side surface of the lens is a vertical surface, and there is some space between each adjacent lens, so the lens or partition frame 6
Even if there is a dimensional error that is unavoidable during manufacturing, the positioning error can be corrected more easily by minute displacement of the lens than in the embodiments described above.

Furthermore, in the embodiments described above, the comb-like lens complexes 10 are used in mesh with each other, but as shown in FIGS. 7 and 8, each lens 21 of a single lens complex 20 is Array pitch and
The lens complex 20 may be mounted on the partition frame 6'' by making the arrangement pitch with the LED chips 2 the same, and in this case, the assembly work efficiency is improved.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to fundamentally solve the conventional light leakage problem when the arrangement pitch of LEDs is miniaturized, and also to provide sufficient mechanical strength.

Moreover, with the above configuration, there is no need to interpose any other member between each lens, and by interlocking the two lens complexes, each lens can be directly and densely arranged, resulting in a finer arrangement. It can be made tight.

In addition, it makes it easier to achieve precision in the outer shape of each lens during the molding process, and it does not hinder the degree of freedom in lens design, making it easier to make the side surfaces sloped.
This inclined surface allows for more complete prevention of light leakage.

Moreover, this inclined surface also improves the "removal property" between the mold and the product during molding.

Furthermore, when two lens composite bodies having the above-mentioned configuration are engaged, alignment is facilitated and the positional accuracy is improved. At this time, adjacent lenses are in line contact and no light leakage problem occurs.

In the lens complex, a side surface different from the adjacent surfaces of the multiple lenses arranged at a distance from each other is formed integrally with the base using transparent synthetic resin, ensuring a thickness equivalent to the width of the side surface of each lens. This makes it possible to provide sufficient mechanical strength.

Furthermore, by interlocking two lens complexes with the above-mentioned configuration, mechanical strength is further improved without light leakage, and positional accuracy is also further improved; This allows for further miniaturization of the array pitch width.

As described above, even when two lens complexes are used according to the present invention, the assembly process is not complicated at all because of the ease of alignment, and there is no problem in mass production.

As described above, according to the present invention, it is possible to provide an LED array light source that is highly mass-producible without causing the problem of light leakage when the arrangement pitch of LEDs is miniaturized.

[Brief explanation of the drawing]

1 to 4 relate to one embodiment of the present invention, FIG. 1A is an exploded perspective view showing a lens complex and a partition frame, and FIG. 1B is a main part showing an LED chip on a printed circuit board. 2 is a sectional front view of the main part, 3 is a plan view of the main part, 4 is an explanatory diagram showing the optical path, and 5 is a perspective view.
6 and 6 are explanatory diagrams showing optical paths by lenses according to other embodiments of the present invention, respectively, and FIGS. 7 and 8 are plan views of main parts showing lens complexes according to still other embodiments of the present invention. FIG. 9 is a cross-sectional front view of a main part showing a conventional example, and FIG. 10 is an explanatory view of the lens according to the conventional example of FIG. 9 made into a fine pitch. 1...Printed circuit board, 2...LED chip, 6,
6', 6''...Partition frame, 7...Small room, 10,20...
...Lens complex, 11, 17, 18, 21...Lens, 16...Target area.

Claims (1)

[Claims] 1. A plurality of LEDs arranged on a substrate and a plurality of lenses each having a convex or planar light incident surface on the lower surface arranged at a distance from each other and arranged on a side surface different from an adjacent surface. It includes a lens complex integrally formed with a base and made of a translucent synthetic resin, and a partition frame formed by arranging a plurality of small chambers with openings at both ends, and the plurality of LEDs are arranged so that the substrate is The lens complex is arranged in each of the small chambers by being disposed in the partition frame from the opening side of one end of the small chamber, and the lens complex is arranged such that the base thereof is different from the side of the partition frame on which the substrate is disposed. The plurality of lenses are placed on different sides, and each of the plurality of lenses is arranged on an opening side of each of the small chambers that is different from the side on which the plurality of LEDs are arranged, and the inner wall of each of the small chambers of the partition frame is
1. An LED array light source characterized in that the lens has a light absorption structure that allows only direct incident light from the LED to enter the lenses and absorbs other light from the LED. 2 The adjacent side surface of each lens with the adjacent lens is:
2. The LED array light source according to claim 1, wherein the lower surface is an inclined surface such that the light entrance surface is smaller than the upper surface exit surface. 3. The lens is inserted a predetermined amount into the chamber of the partition frame so that a part of the side surface of each lens adjacent to the adjacent lens comes into contact with the upper edge of the chamber of the partition frame. The LED array light source according to scopes 1 and 2. 4. Each lens in the lens complex corresponds to every other LED of the plurality of LEDs, and by interlocking the two lens complexes, lenses can be arranged to correspond to all of the plurality of LEDs. An LED array light source according to claim 1, characterized in that: 5. A patent claim characterized in that in a state in which the two lens complexes are meshed together, at least an inclined surface is formed on the adjacent surface of each lens to the adjacent lens so that the adjacent lenses are in line contact with each other. The LED array light source according to item 4.