JP3133242B2 - LED line light source device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reading a document when transmitting a facsimile,
The present invention relates to a line light source device used for erasing a latent image on a photosensitive drum in a copying machine, and more particularly, to a line light source device using an LED as a light source.

[0002]

2. Description of the Related Art FIG. 7 shows an example of the configuration of a conventional LED line light source device 90 of this type. A plurality of LED chips 92 are mounted on a substrate 91 in a straight line. A substantially cylindrical lens 93 whose axis is parallel to the straight line on which the LED chip 92 is mounted is mounted together with a lamp house 94.

At this time, the interval D when mounting the LED chip 92 is basically uniform, but if a bright portion is required in light distribution characteristics, the portion D of the bright portion is required. This is addressed by reducing the distance D between the LED chips 92. If a dark part is required, the distance D
It is dealt with by making it wider.

In the figure, reference numeral 95 denotes a security resistor which is connected in series with the LED chip 92 to the power supply to prevent an excessive current from flowing.
Are provided for each of the LED chips 92, so that the same number as the LED chips 92 is naturally provided.

[0005]

However, in the above-described conventional LED line light source device 90, the LED light source device 90 is required at the time of production.
Advanced equipment and work contents are required, 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, and as a result, the LED line light source device 90 has the problem of being expensive.

Further, a large number of LED chips 92 to be used are required, and accordingly, the number of security resistors 95 is also large. At the time of lighting, the heat generated by the LED chips 92 and the security resistors 95 causes a temperature rise in the LED line light source device 90. As a result, for example, the LED chip 92 disposed at the center has a problem in performance such as a decrease in brightness and uneven illumination, and solving these points has been an issue.

[0007]

According to the present invention, as a specific means for solving the above-mentioned conventional problems, an LED is used as a light source, and is wide in a predetermined direction with respect to an object to be illuminated. In the LED line light source device that generates a substantially linear irradiation light with a narrow width in the direction in which the LED line light source device
A transparent member is formed in a substantially cylindrical shape having light source light capturing portions provided at both ends, and a portion of the outer peripheral surface of the cylindrical portion opposite to the irradiation direction is an isosceles having a direction orthogonal to the cylindrical axis. An object is to provide an LED line light source device, comprising: a lens provided with a triangular knurled cut; and a pair of LED lamps facing each of the light source light capturing portions of the lens. Is to solve.

[0008]

Next, the present invention will be described in detail based on an embodiment shown in the drawings. 1 and FIG.
Is an LED line light source device according to the present invention. The LED line light source device 1 is used, for example, for reading a document at the time of facsimile transmission.
Using the ED as a light source, a substantially linear irradiation light having a large width in one predetermined direction and a small width in a direction orthogonal to the predetermined direction is similar to the conventional example.

A lens 2 is provided in the LED line light source device.
This lens 2 has an axis Z on the wide side of the irradiation light.
Is similar to the conventional example in that the lens has a substantially cylindrical shape having a total length L. However, according to the present invention, both ends of the lens in the direction of the axis Z are cut, for example, at a right angle to the axis Z and smooth. The surface is provided with a light source light capturing portion 2a having a finish.

[0010] Each of the light source light intake portions 2a provided at both ends of the lens 2 is, for example, a dome-shaped resin mold, and is a finished LED as a component.
The lamp 3 faces each other, and the light source
The light from the ED lamp 3 is taken into the lens 2. Therefore, in the present invention, the LED lamp 3 as the light source is used.
Is necessarily limited to two.

The lens 2 is attached to a lamp house 4 and an opening 4a provided in the lamp house 4.
Irradiates light in a predetermined direction from the lens 2, and at this time, the cutting direction is orthogonal to the axis Z direction of the lens 2 on the outer peripheral surface opposite to the irradiation direction of the lens 2,
A knurl cut 2b having a cross section along the axis Z direction having an isosceles triangular shape 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 take-in portion 2a in the irradiation direction.
The light distribution characteristics required for the LED line light source device 1 are as follows:
Most of them are determined by the performance of the knurl cut 2b.

First, the brightness of the LED line light source device 1 is improved by increasing the depth H of the knurled cut 2b, and the apex angle α of the knurled cut 2b having an isosceles triangular shape is optimized. However, when the depth H is increased, the pitch P between the knurl cuts 2b is widened, causing uneven brightness in the light distribution characteristics.

Therefore, in the present invention, the depth H
Is specifically fixed at approximately 0.2 mm, and the apex angle α
Is adjusted to obtain the maximum value of the brightness within a range that does not cause uneven brightness in the LED line light source device 1. According to the result of the study by the inventors, the apex angle α is set to 100 ° to 120 °.
When set as °, it was confirmed that the amount of light emitted from the opening 4a became maximum.

The illuminance curve S1 shown in FIG. 4 is a light distribution characteristic along the axis Z direction of the lens 2 in the above-described configuration.
Is formed as a constant width over the entire length L in the direction of the axis Z. In the illuminance curve S1, the brightness is reduced at the center of the lens 2 farthest from the LED lamps 3 provided at both ends of the lens 2. Therefore, in the present invention, this phenomenon is caused by the knurl cut 2b and the axis of the lens 2. This is dealt with by adjusting the width W in the direction perpendicular to Z depending on the location.

FIG. 5 shows the state of adjustment of the width W of the knurl cut 2b.
In the portion a, that is, the portion close to the LED lamp 3, the width W of the knurled cut 2b is minimized, and is gradually increased as the distance from the knurled cut 2b is increased, so that the width becomes the maximum width at the center, that is, a position where L / 2 with respect to the entire length L. I have to. It is necessary to adjust the ratio of the width W of the knurled cut 2b according to the overall length of the lens 2. In this embodiment, when the ratio is around 1: 4, the flat light distribution shown by the illuminance curve S2 in FIG. Characteristics were obtained.

The illuminance curve T1 shown in FIG. 6 shows the light distribution characteristics in the direction orthogonal to the axis Z of the lens 2 in the above configuration. It is preferable that no significant unevenness occurs on the light distribution characteristics. Therefore, in the present invention, the cut surface of the knurl cut 2b is flattened as shown by the illuminance curve T2 in FIG. 6 by performing fine unevenness processing by means such as sandblasting.

Next, the LED of the present invention having the above configuration
The operation and effect of the linear light source device 1 will be described. First, the LED used as the light source may be changed from a chip-shaped LED to a lamp-shaped LED, and may be mounted on a dedicated machine such as a mounting machine or a wire bonding machine. What requires high-level work contents can be manufactured with tools and simple work contents. Also, the number of LEDs used is drastically reduced to only two, so that the amount of heat generated at the time of 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, the light source may be replaced with an incandescent light bulb.

[0019]

As described above, according to the present invention, the transparent member is formed in a substantially cylindrical shape having light source light receiving portions provided at both ends, and the portion on the outer peripheral surface of the cylindrical shape is opposite to the irradiation direction. A lens provided with a knurled cut in an isosceles triangular shape in a direction perpendicular to the cylindrical axis, and a pair of Ls opposed to the respective light source light capturing portions of the lens.
By using an LED line light source device composed of an ED lamp, the light source can be changed from a dedicated machine such as a mount machine or a wire bond machine to an LED chip that requires advanced work contents.
It is possible to change to an LED lamp that requires only a tool and simple work contents, to improve productivity, and to achieve an extremely excellent effect on cost reduction of this type of LED line light source device.

In addition, the number of LEDs has conventionally been required to be at least about ten, but has been drastically reduced to only two.
In this aspect, the cost can be reduced, and the reduction in the number reduces the rise in the temperature of the LED line light source device at the time of lighting. It is also effective in improving the performance of various types of LED line light source devices.

[Brief description of the drawings]

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

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

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

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

FIG. 5 is an explanatory view showing an installation state of a knurl cut in the same embodiment.

FIG. 6 is a graph showing light distribution characteristics 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 exploded state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... LED line light source device 2 ... Lens 2a ... Light source light take-in part 2b ... Knurl cut 3 ... LED lamp 4 ... Lamp house W ... Knurl cut width Z ... Lens axis

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-8-43633 (JP, A) JP-A-9-61633 (JP, A) JP-A-7-14414 (JP, A) JP-A-7-144 245676 (JP, A) JP-A-5-232323 (JP, A) JP-A-62-287206 (JP, A) JP-A-6-21940 (JP, U) JP-A-63-44563 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) H04N 1/04 G02B 6/00

Claims (4)

(57) [Claims] 1. An LED line light source device which uses a LED as a light source and generates a substantially linear irradiation light which is wide in one predetermined direction and narrow in a direction orthogonal to the object to be illuminated. The light source device is formed in a substantially cylindrical shape with a transparent member and light source light capturing portions provided at both ends, and a portion of the outer peripheral surface of the cylindrical shape opposite to the irradiation direction is orthogonal to the cylindrical axis. An LED line comprising: a lens provided with a knurl cut in an isosceles triangular shape in a direction to be directed; and a pair of LED lamps opposed to the respective light source light intake portions of the lens. Light source device. 2. The LED line light source device according to claim 1, wherein the knurl-cut isosceles triangle has an apex angle of 100 ° to 120 °. 3. The cut surface of the knurl cut is subjected to fine unevenness processing.
Or the LED line light source device according to claim 2. 4. A straight to cylindrical axis of the knurling cuts
Claim 1, characterized in that the width provided in a direction exchange is changed according to light distribution characteristics required for the illumination light, LED line light source of claim 2 or claim 3, wherein.