JPH09163079A - Led linear light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the cost of an LED linear light source device by composing the device of the lens which is provided with light source light fetching parts at the both end and for which a knurled cut is performed and a pair of LED lamps. SOLUTION: At the both ends in the axis Z direction of the lens 2 of an LED linear light source device, light source light fetching parts 2a which are cut perpendicularly to the axis Z direction and are finished to a smooth surface, for instance, are provided. In each of the light source light fetching part 2a at the both ends of the lens 2, the LED lamps are placed opposite to each other and the light from the LED lamps 3 is fetched from this light source light fetching part 2a to the inside of the lens 2. The irradiating light from the opening part 4a provided on the lamp house 4 on which this lens 2 is mounted to a prescribed direction is generated. At this time, on the outer peripheral surface which is the opposite side of the irradiating direction of the lens 2, a knurled cut orthogonally crossing a cutting direction with the axis Z direction of this lens 2 and making the cross section along the axis Z direction into an isosceles triangle is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, when a document is read during transmission of a facsimile, or when a PPC is used.
The present invention relates to a linear light source device used when a latent image on a photosensitive drum is erased in a copying machine, and more specifically to a linear light source device using a light source as an LED.

[0002]

FIG. 7 shows an example of the structure of a conventional LED line light source device 90 of this type. A plurality of LED chips 92 are linearly mounted on a substrate 91, and the substrate 91 is also provided. A substantially cylindrical lens 93 whose axis is parallel to the straight line on which the LED chip 92 is mounted is attached together with the lamp house 94.

At this time, the distance D when mounting the LED chip 92 is basically uniform, but when a bright portion is required for the light distribution characteristics, that portion is required. This is dealt with by narrowing the distance D between the LED chips 92, and when a dark portion is required, the distance D
It is dealt with by widening.

Reference numeral 95 in the figure is a safety resistor connected to the power source in series with the LED chip 92 to prevent an excessive current from flowing, and this safety resistor 95
Since the LED chips 92 are provided for each LED chip 92, the same number as the LED chips 92 is naturally provided.

[0005]

However, in the above-mentioned conventional LED line light source device 90, the L line light source device 90 is produced at the time of production.
Advanced equipment and work contents such as a mounting process of the ED chip 92 on the substrate 91 and a wiring process using the wire bonder to the LED chip 92 accompanying this are required, and as a result, the LED line light source device is obtained. 90 is expensive.

Further, a large number of LED chips 92 to be used are also required, and accordingly, a large number of safety resistors 95 are also generated. When the LED chips 92 and the safety resistors 95 generate heat, the temperature of the LED line light source device 90 rises. As a result, for example, the LED chip 92 arranged in the central portion has a problem in performance such as a decrease in luminance and uneven illumination, and it has been a problem to solve these problems.

[0007]

As a concrete means for solving the above-mentioned conventional problems, the present invention uses an LED as a light source and has a wide width in a predetermined direction with respect to an object to be illuminated and is orthogonal thereto. In the LED line light source device that generates substantially linear irradiation light with a narrow width in the direction of
A transparent member is formed into a substantially cylindrical shape with light source light-intake portions provided at both ends, and an isosceles side perpendicular to the axis of the cylindrical shape is formed on a portion of the outer peripheral surface of the cylindrical shape opposite to the irradiation direction. An LED line light source device comprising: a lens having a triangular knurl cut; and a pair of LED lamps facing the light source light receiving portions of the lenses. Is the solution.

[0008]

Next, the present invention will be described in detail based on an embodiment shown in the drawings. 1 and FIG.
The LED line light source device according to the present invention is shown by, and the LED line light source device 1 is used, for example, for reading an original at the time of transmission of a facsimile.
Similar to the conventional example, the ED is used as a light source to generate substantially linear irradiation light having a wide width in a predetermined direction and a narrow width in a direction orthogonal to the predetermined direction.

Further, the LED line light source device has a lens 2
Is provided, and the lens 2 has an axis Z on the side where the irradiation light is wide.
It is also similar to the conventional example in that it has a substantially cylindrical shape with a total length L, but according to the present invention, both ends in the axis Z direction of the lens are cut and smoothed, for example, at right angles to the axis Z direction. A light source light receiving section 2a whose surface is finished is provided.

Then, for example, a dome-shaped resin mold is applied to each of the light source light receiving portions 2a provided at both ends of the lens 2 to complete the LED as a component.
The lamp 3 is confronted, and the light from the light source light receiving portion 2a is connected to the L
The light from the ED lamp 3 is taken into the lens 2. Therefore, in the present invention, the LED lamp 3 which is the light source
The number of is necessarily limited to two.

The lens 2 is attached to a lamp house 4, and an opening 4a is provided in the lamp house 4.
Light is generated in a predetermined direction from the above, and at this time, on the outer peripheral surface opposite to the irradiation direction of the lens 2, the cutting direction is made orthogonal to the axis Z direction of this lens 2,
A knurled cut 2b having an isosceles triangular cross section along the axis Z is provided.

Here, the knurl cut 2b will be described in more detail.
Is for reflecting the light of the LED lamp 3 incident from the light source light receiving section 2a toward the irradiation direction, and
The light distribution characteristics required for the LED line light source device 1 are as follows.
Most will be determined by the performance of the knurled cut 2b.

First, the brightness of the LED line light source device 1 is improved by increasing the depth H of the knurl cut 2b, and the apex angle α of the isosceles triangular knurl cut 2b is optimized. (See FIG. 3), the pitch P between the knurled cuts 2b becomes wider when the depth H is increased, which causes uneven brightness in the light distribution characteristics.

Therefore, in the present invention, the depth H of the cut is
Is fixed to approximately 0.2 mm, and the apex angle α
Is obtained to obtain the maximum brightness of the LED line light source device 1 in a range in which there is no unevenness in brightness, and the result of examination by the inventor shows that the apex angle α is 100 ° to 120 °.
It was confirmed that the amount of light emitted from the opening 4a was maximized when the angle was set as °.

The illuminance curve S1 shown in FIG. 4 shows the light distribution characteristic along the axis Z direction of the lens 2 having the above-mentioned structure. At this time, the knurl cut 2b is used for the lens 2.
Is formed to have a constant width over the entire length L in the axis Z direction. In the illuminance curve S1, there is a decrease in brightness at the center of the lens 2 that is farthest from the LED lamps 3 provided at both ends of the lens 2. Therefore, in the present invention, this phenomenon occurs in the axis of the lens 2 of the knurl cut 2b. This is dealt with by adjusting the width of the width W in the direction perpendicular to Z depending on the location.

FIG. 5 shows a state in which the width W of the knurled cut 2b is adjusted. The light source light receiving section 2 of the lens 2 is shown in FIG.
The width W of the knurled cut 2b is minimized in the portion a, that is, in the portion close to the LED lamp 3, and is gradually increased as the distance is increased so that the width becomes maximum at the center, that is, at a position of L / 2 with respect to the total length L. I have to. The ratio of the width W of the knurl cut 2b needs to be adjusted according to the total length of the lens 2, but in this embodiment, when the ratio is around 1: 4, the flat light distribution shown by the illuminance curve S2 in FIG. The characteristics were obtained.

The illuminance curve T1 shown in FIG. 6 is the light distribution characteristic in the direction orthogonal to the axis Z of the lens 2 in the above-mentioned configuration, and the LED line light source device 1 also has this characteristic. It is preferable that no remarkable unevenness is generated on the light distribution characteristics. Therefore, in the present invention, the cut surface of the knurled cut 2b is flattened as shown by the illuminance curve T2 in FIG. 6 by performing fine unevenness treatment by means such as sandblasting.

Next, the LED of the present invention having the above structure
The operation and effect of the linear light source device 1 will be described. First, the LED used as a light source may be changed from a chip type to a lamp type, and a dedicated machine such as a mount machine or a wire bond machine may be used. What requires a high level of work content can be manufactured with tools and simple work content. In addition, the number of LEDs used is drastically reduced to only two, so the amount of heat generated during lighting is also reduced.
In the present invention, since the light source may be the LED lamp 3 in the form of a single component, it can be naturally replaced with an incandescent lamp.

[0019]

As described above, according to the present invention, a transparent member is formed into a substantially cylindrical shape having light source light receiving portions at both ends, and the portion of the cylindrical outer peripheral surface opposite to the irradiation direction. A lens having an isosceles triangular knurl cut in a direction orthogonal to the cylindrical axis, and a pair of Ls facing the respective light source light receiving portions of the lens.
By using an LED line light source device composed of an ED lamp, the light source is a dedicated machine such as a mount machine or a wire bond machine, and an LED chip that requires a high level of work content.
It is possible to change to an LED lamp that requires only a tool and simple work contents, improve productivity, and achieve an extremely excellent effect in reducing the cost of this type of LED line light source device.

Also, the number of LEDs required to be at least about 10 in the past has been drastically reduced to only 2,
In this respect as well, it is possible to reduce the cost, and by reducing this number, the temperature rise of the LED line light source device at the time of lighting is also reduced, and the point that the brightness decrease due to the temperature rise with the lapse of use time is also eliminated. It also has an excellent effect in improving the performance of various LED line light source devices.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of an LED line light source device according to the present invention in a partially exploded state.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an enlarged cross-sectional view of a main part of the same embodiment.

FIG. 4 is a graph showing an axial light distribution characteristic of a lens in the same embodiment.

FIG. 5 is an explanatory diagram showing a knurled cut installation state in the same embodiment.

FIG. 6 is a graph showing a light distribution characteristic in a direction orthogonal to an axis of a lens in the same embodiment.

FIG. 7 is a perspective view showing a conventional example in a partially disassembled state.

[Explanation of symbols]

 1 ... LED line light source device 2 ... Lens 2a ... Light source light capturing part 2b ... Knurl cut 3 ... LED lamp 4 ... Lamp house W ... Knurl cut width Z ... Lens axis

Claims (4)

[Claims] 1. An LED line light source device, which uses an LED as a light source and generates substantially linear irradiation light having a wide width in a predetermined direction and a narrow width in a direction orthogonal to the illumination target, in the LED line light source device. The light source device is formed in a substantially cylindrical shape with a light source light receiving portion provided at both ends of a transparent member, and a portion of the outer peripheral surface of the cylindrical shape opposite to the irradiation direction is perpendicular to the cylindrical axis. 2. An LED line light source device, comprising: an isosceles triangular knurled lens and a pair of LED lamps facing the respective light source light receiving portions of the lens. 2. The LED line light source device according to claim 1, wherein an apex angle of the knurled isosceles triangular shape is 100 ° to 120. 3. The surface of the knurled cut is finely textured.
Alternatively, the LED line light source device according to claim 2. 4. The width of the knurl cut provided in a direction perpendicular to the cylindrical axis is changed according to the light distribution characteristics required for the irradiation light. Item 2. The LED line light source device according to item 2 or item 3.