JPH0644157U - Line lighting device - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a linear illumination device with less unevenness in the brightness of the light source. [Structure] A conventionally developed LED array is provided with a semi-cylindrical lens, and the curvature of this lens is focused on an extension line in the middle between arrayed light emitting elements. [Effect] The brightness unevenness in the x direction of the line illumination device can be made uniform.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a line-shaped lighting device using a light emitting diode element that can be effectively used as a lighting device for an image reading sensor for a dry copying machine or a facsimile.

[0002]

[Prior art]

 As a lighting device for an image reading unit of a dry copying machine or a facsimile, a light-emitting diode element is one-dimensionally arranged on a conventional discharge tube (cold-cathode tube, fluorescent lamp, etc.) or a wiring board (hereinafter referred to as an LED array). However, LED arrays that are easy to achieve small size and low price as an illumination light source are currently line-shaped lighting due to downsizing, high functionality, and low cost of copiers and facsimiles. It is becoming the main body of equipment.

[0003]

[Problems to be solved by the device]

 FIG. 1 is a perspective view showing an example of a linear illumination device using the above LED array. This lighting device has a large number of light emitting diodes 2 arranged one-dimensionally on a printed wiring board 1. These are electrically and mechanically connected to the printed wiring board by soldering, and all the light emitting diodes are turned on at the same time. It has electrical wiring. In this line-shaped lighting device, the light-emitting diode used for the light-emitting source is a point-shaped light source, and the arrangement causes the original surface near the light-emitting source to be bright and the original surface in the middle between the light-emitting sources to be dark. Occurs, which necessitates a light amount correction circuit in the image reading sensor, which is one obstacle to lowering the price.

[0004]

[Means for Solving the Problems]

 Therefore, as a result of studies made by the present inventors to solve the above problems, it was found that the above problems can be solved by placing a semi-cylindrical lens on the LED array and controlling the condensing density of the lenses. The present invention has been completed and the gist of the invention is that a large number of light emitting diode elements are arranged one-dimensionally, and the curvature of the lenses is arranged by a semi-cylindrical lens in front of the light emitting source. This is a line-shaped illumination device characterized in that a lens having a curvature that collects light from a light-emitting diode element is arranged between the elements.

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view of a light emitting element array in which LED light emitting elements are arranged on a printed wiring board 1. FIG. 2 is a perspective view showing an outline of the linear lighting device of the present invention. In the figure, 21 is a printed wiring board, 22 is a light emitting diode element, 201 is a semi-cylindrical lens which is a feature of the present invention, and P is an intermediate point between the light emitting elements. By setting the curvature so that the focal point of this lens is aligned with the point P _{1 of the} illuminated object on the extension line in the middle of the light emitting element, the conventional darkest point P ₁ is brightened by the condensing effect of the lens. , conventional lightest point uniform brightness unevenness in brightness and becomes line axis substantially equal to that of the point P ₁ as a result lower than the condensing density points P ₁ from the difference of the distance of the focal the P ₂ have illuminated effect It is possible to obtain a line-shaped illuminating device.

[0006]

[Effect of device]

 The present invention makes it possible to make the brightness unevenness in the array direction of the light emitting diodes smaller than that of a conventional linear lighting device using only an LED array, and the absolute value of the brightness can be increased by the lens. When used as a line-shaped lighting device for image reading such as facsimiles, it is expected to have the effects of downsizing, speeding up, and reducing the number of parts.

[Brief description of drawings]

FIG. 1 is an LED for an image reading device which has been conventionally used.
Schematic of the array.

FIG. 2 is a schematic configuration diagram of a linear illumination device of the present invention.

[Explanation of symbols]

1, 21 Printed wiring board 2, 22 Light emitting diode 23 Illuminated object 201 Kamaboko lens P ₁ Light emitting diode center point P ₂ Light emitting diode array midpoint

Claims (1)

[Scope of utility model registration request] 1. A light emitting source in which a large number of light emitting diode elements are arranged in a one-dimensional manner, and a semi-cylindrical lens on the front surface of the light emitting source, and the curvature of the lens is located at an intermediate point between the arrayed light emitting diode elements. A line-shaped illuminating device having a curvature so that light from an element is condensed.