JPH0520041Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an LED bar-shaped light source that can be applied to, for example, facsimile machines, copying machines, and the like.

[Conventional technology]

Illumination devices with a bar-shaped light source have been used for various purposes.For example, bars using LEDs have recently been used as a light source for reading images on the document surface in facsimile machines, copying machines, etc. Shape light sources are increasingly being used.

In this case, while the document is relatively moved in one direction, an LED bar-shaped light source using, for example, a light emitting diode array (hereinafter referred to as an LED array), , a line-shaped illumination light is emitted, and the reflected light reflected by the original is sent to a light receiving device, such as a CCD.
By reading the image while scanning in the scanning direction, the above-mentioned reading operation is sequentially repeated as the document moves, and the image on the surface of the document is read.

The above-mentioned LED bar-shaped light source includes, for example, as shown in FIG. 3, an LED array 2 mounted in a line on a substrate 1 extending in the longitudinal direction, and a lens 3 disposed above the LED array 2. It is comprised of a resin lamp house 4 that prevents light from the LED array 2 from leaking to the sides.

In this case, if the lens 3 rises,
The distance between each LED chip of the LED array 2 and the lens 3 changes, and on the document surface illuminated by the LED array 2, the illuminance distribution by the LED array 2 changes along the central axis of the LED array 2. Therefore, the illumination width with a predetermined illuminance varies greatly. If the image of the illuminated document surface is read in a straight line in the scanning direction, the read image will have shading due to uneven illumination, making it impossible to read the image accurately.

Therefore, in order to prevent the lens 3 from floating, in the conventional LED bar-shaped light source, there are fixed heights provided on the substrate 1 inside the lamp house 4 at predetermined intervals along the central axis. The lens 3 is attached to the substrate 1 by bringing the lower edge of the lens 3 into contact with the crosspiece 4a (see Figure 4).
The lens 3 is positioned at a predetermined distance from the LED array 2, and the lens 3 is held near the upper edge of the inner wall of the lamp house 4 by the elastic force of the resin constituting the lamp house 4.

[The problem that the idea attempts to solve]

However, in the above configuration, since the lens 3 is in line contact with the inner wall of the lamp house 4, unless the molding precision of the lamp house 4 is increased, the inner wall of the lamp house 4 will be in contact with the lens 3. At least part of the contact has been lost,
This results in the lens 3 floating up.
Furthermore, when a downward force F is applied to the lens 3 from above, this force acts to push the inner wall of the lamp house 4 outward with a force f, and at this time, slight accuracy errors on the inner wall of the lamp house 4 are This creates a difference in the force f on the two inner walls, which causes the lens 3 to shift relative to the LED array 2. As a result, the illuminance distribution by the LED array 2 on the document surface illuminated by the LED array 2 is adjusted accordingly.
It is not uniform along the central axis of the LED array 2,
Therefore, it becomes impossible to perform accurate image reading.

In view of the above points, the present invention has been developed to prevent the lens from floating and to provide uniform illumination in the scanning direction of the document surface, for example.
The purpose is to provide an LED bar-shaped light source.

[Means to solve the problem]

The above purpose, according to the present invention, is to
An LED bar that includes an LED array equipped with LED chips and a cylindrical lens having a central axis parallel to the column direction above the LED array, and irradiates a line-shaped illumination light extending in the column direction. In the light source, a lamp house for preventing light from the LED array from leaking to the side has an inner wall extending vertically in an upper region at intervals approximately equal to the width of the lens, and a lamp house that prevents light from leaking to the side from the LED array. The LED must be kept at a predetermined distance
This is achieved by forming a plurality of crosspieces that are arranged at predetermined intervals along the central axis of the LED array and extend diagonally upward in the form of a ridge from the central axis of the LED array toward the inner walls of the lamp house on both sides.

[Effect]

According to this invention, the lenses are placed on the ridge-shaped portions of the crosspieces arranged at predetermined intervals along the LED array, which extend diagonally upward toward the inner wall of the lamp. It can be positioned in a predetermined position relative to this LED array.
In addition, since this lens loosely fits into the inner wall of the lamp house that extends vertically at intervals approximately equal to the lens width, the ridge-shaped portion of each crosspiece formed between the inner walls of the lamp house Since the lenses are positioned and held by point contact, it is not necessary to form the entire lamp house with high precision, and only the crosspieces need to be formed with high precision.

Further, when a downward force is applied to the lens from above, this force does not act to push the inner wall of the lamp house outward. Therefore, the lens is not partially lifted, and more uniform illumination without unevenness can be achieved, for example, in the scanning direction of the document surface.

〔Example〕

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 shows an embodiment of an LED bar-shaped light source according to the present invention, and this LED bar-shaped light source 10 includes:
Multiple LED chips 1 on a long board 11
3 in a row at predetermined intervals, and an LED array 12 formed by die bonding the LEDs.
a lamp house 14 extending upward along both longitudinal edges of the substrate 11 on which the arrays 12 are arranged;
The above is applied to the inner wall 14a of this lamp house 14.
At predetermined intervals along the longitudinal direction of the LED array 12,
That is, each LED chip 1 constituting the LED array 12
A plurality of crosspieces 1 formed to be located between 3
5, and a cylindrical lens 16 having both sides near the top of the lamp house 14 and a lower edge touching the crosspiece 15, and having a central axis parallel to the longitudinal direction of the LED array 12. It is composed of.

Here, the inner wall 14a of the lamp house 14 extends vertically in its upper region, ie, in the region where it should contact the lens 16, with a spacing approximately equal to the diameter of the lens, as shown.

Further, each of the beams 15 is arranged at right angles to the center axis of the LED array 12, that is, the lamp houses 14 on both sides
The lens 16 is positioned and held by the V-shape formed by the two pairs of ridge-like portions 15a. Note that if the ridge-shaped portion 15a of the crosspiece 15 is formed in a V-shape at least in the area where it should contact the lens 16, other portions, for example, the central portion as shown in the figure, may be formed so as to extend in the horizontal direction. You can.

The LED array according to the present invention is constructed as described above, and the lenses 16 are arranged along the LED array 12 at predetermined intervals on the inner wall 14a of the lamp house 14.
The ridge-shaped portion 15a of the crosspiece 15 formed between the LED array 12 is positioned and held at a predetermined position with respect to the LED array 12, and
It will fit loosely into the inner wall 14a of the lamp house 14, which extends vertically at intervals approximately equal to the diameter of the lens 16. Therefore, the ridge-shaped portion 15a of each crosspiece 15 formed between the inner walls 14a,
The lens 16 is positioned and held by point contact, respectively.

Furthermore, even if a downward force F is applied to the lens 16 from above, this force F
The force f' does not act to push the inner wall 14a of the crosspiece 15 outward, but acts equally on the pair of ridge-shaped portions 15a of the crosspiece 15. Therefore, the lens 16 can be reliably fixed without shifting or floating relative to the LED array 12.
Positioning at a predetermined position with respect to the LED array 12,
It will be retained.

In this way, the lens 16 can be accurately positioned and held with respect to the LED array 12 by simply maintaining and managing only the roundness of the lens 16 and the rising angle θ of the ridge-shaped portion 15a (see FIG. 1) with high precision. As a result, the amount of deviation from the center of the illuminance distribution of the LED array 12 due to each LED chip 13 described above is greatly reduced, which is suitable for, for example, uniform image reading with high linearity in the scanning direction of the document surface. Line-shaped illumination can be realized.

Although the LED bar-shaped light source of the present invention has been mainly explained using an example of a lighting device for image reading such as a copying machine or a facsimile machine, it is not limited to this and can be applied to various lighting sources such as for decoration. Needless to say.

[Effect of idea]

As described above, according to the present invention, the lens
of the crosspieces arranged at predetermined intervals along the LED array.
an inner wall of the lamp house that can be positioned in a predetermined position with respect to the LED array by a ridge-like portion extending laterally and diagonally upward toward the inner wall of the lamp and extending vertically at intervals approximately equal to the width of the lens; It will fit loosely.

Therefore, since the ridge-shaped parts of each crosspiece formed between the inner walls of the lamp house position and hold the lens through point contact, it is no longer necessary to form the entire lamp house with high precision, and only the crosspieces can be formed. It may be formed with high precision.

Further, when a downward force is applied to the lens from above, this force does not act to push the inner wall of the lamp house outward, so the lens does not partially lift up. Therefore, even if this light source is used as illumination for image reading, it is possible to provide more uniform illumination without unevenness in the scanning direction of the document surface. Accurate image reading can be achieved by reading in a straight line along.

Thus, according to the present invention, there is provided an LED bar-shaped light source that can provide uniform illumination without causing the lens to float.

[Brief explanation of the drawing]

FIG. 1 is a schematic view showing an embodiment of the LED bar-shaped light source according to the present invention, and FIG. 2 is a partial sectional view showing the inner wall of the lamp house of the embodiment of FIG. Figure 3 is a schematic diagram showing an example of a conventional LED bar-shaped light source.
FIG. 4 is a partial sectional view showing the inner wall of the lamp house of the conventional example shown in FIG. 10... LED bar-shaped light source, 11... Board, 1
2...LED array, 13...LED chip, 14
...Lamp house, 14a...Inner wall, 15...
Crosspiece, 15a...ridge-shaped portion, 16...lens.

Claims (1)

[Claims for Utility Model Registration] An LED array including LED chips arranged in a row, and a cylindrical lens having a central axis parallel to the row direction above the LED array,
Irradiate the line-shaped illumination light extending in the direction of the above columns.
In the LED bar-shaped light source, a lamp house that prevents light from the LED array from leaking to the side has an inner wall extending vertically in an upper region at intervals approximately equal to the width of the lens, and a lamp house that prevents light from leaking to the side from the LED array. In order to maintain a predetermined distance from the LED array, the LED array is arranged at a predetermined interval along the central axis of the LED array, and extends diagonally upward in the form of a ridge from the central axis of the LED array toward the inner walls of the lamp house on both sides. An LED bar-shaped light source characterized by having a plurality of extending crosspieces.