JP2877312B2 - Photoelectric conversion element array - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a photoelectric conversion element array used as a reading light source for a copying machine, a facsimile, an image scanner, and the like.

(Prior art) LED arrays are used as light sources for reading in plain paper copying machines, facsimile machines, image scanners, etc., but the reality is that they are applied as so-called contact sensors including CCDs, and others have a reduced lens type. Sensors are also used, and the latter has the disadvantage that LEDs other than CCDs are more expensive than the former.

This is because in the latter method, the LED is
In general, the elements are arranged in a straight line, and a lens that focuses the radiated light from the object to be processed on the CCD is placed in the middle, and this lens is usually given a special shape to ensure focusing. It is a target.

Therefore, this method has the disadvantage that parts other than CCDs become expensive, so in the case of models with intense Cost competition, the range of use of the above-mentioned contact sensor is rather widened in recent years. ing.

The method of using this contact sensor is
Irradiate with a light source placed about 10 cm away and place the reflected light near it. This is a method of making judgments using a line sensor composed of a CCD. For this purpose, the irradiation light from the light source must accurately irradiate a predetermined position on the object to be processed.

The reason is that the LED element used as this light source uses a focused light beam to increase its brightness, irradiates a predetermined position of the object with high precision, and the vertical component in the irregularly reflected light is a line sensor consisting of a CCD This is because a method of detecting by the method is adopted.

By the way, the LED array used for the contact sensor is the fourth.
As shown in FIGS. A and b, LED elements 51... (GaP green) are arranged in a straight line and electrically connected to a wiring layer (not shown) formed on the surface of the prepared wiring board 50. Further, a transparent molded body 52 having a lens effect is arranged on the wiring substrate 50 so as to be opposed to the transparent molded body 52, and then bonded. In the transparent molded body 52 formed by an injection molding method using a mold, a portion facing the LED elements 51 is removed to form a concave portion, but a cross section of the concave portion 53 parallel to the boundary surface with the wiring board 50 is formed. The corners 54 are formed as shown in the sectional views shown in FIGS. 4a and 4b, and the frequency of irregular reflection increases.

(Problems to be Solved by the Invention) In a photoelectric conversion element array such as an LED having the above-described structure, a corner is formed in a concave portion.
The angle between the radiated light and the concave part becomes smaller at this corner, and the ratio of the scattered light generated by the reflection on the concave part wall to the vertical light becomes very large, so that the radiated light can be effectively extracted out of the transparent molded body. could not.

In addition, the increase in the scattered light component causes a decrease in the luminance of the effective illuminance area, which causes a problem that the luminance required for the line sensor is not satisfied.

An object of the present invention is to provide a novel photoelectric conversion element array in which the above-mentioned disadvantages have been eliminated, and in particular, to effectively emit radiation having a predetermined luminance.

[Configuration of the invention]

(Means for Solving the Problems) In order to achieve this object, in a photoelectric conversion element array according to the present invention, a wiring board, a plurality of photoelectric conversion elements arranged linearly on the wiring board, and A transparent molded body that covers these photoelectric conversion elements and is provided with an independent concave portion that reflects radiation light of the photoelectric conversion element at a position facing the photoelectric conversion element; It is characterized in that the cross section parallel to the surface has a closed curve shape. Further, the shape of the recess is such that the cross section is a perfect circle, the shape of the recess is an ellipse, the cross section of the recess is rectangular, and the shape of the recess is It is also characterized in that the curvature is set at the corner of the cross section of the.

(Operation) In the transparent molded body having a lens effect that covers the photoelectric conversion element, the reflected light on the inner wall of the concave is formed by making the radiated light enter the transparent molded body at an angle closer to the vertical than in the conventional case. In this way, the emitted light having the required brightness is efficiently emitted to the outside.

Therefore, the function of the photoelectric conversion element array is improved because the light which has been lost can be effectively used.

(Embodiment) The present invention will be described in detail with reference to FIGS.

As is apparent from the perspective view of the photoelectric conversion element array 1 according to the present invention shown in FIG. 2, a transparent molded body 3 having a lens effect is adhered to the wiring board 2 to be integrated.

The transparent molded body 3 is molded by an injection molding method using a mold, and a hemispherical portion 4 is formed on the top of the transparent molded body 3 in order to efficiently extract the radiation light of a photoelectric conversion element described later.

On the other hand, for example, a glass-epoxy substrate can be applied as the wiring substrate 2, and a wiring layer (not shown) is provided on the surface of the wiring substrate 2 by a usual method, and a GaP green LED device for the photoelectric conversion device 1 is linearly arranged here. And electrical connection is made by a thermocompression bonding method using a bonding wire so that a current can be supplied from the outside.

Injection mold using mold
In the transparent molded body 3 formed by the ion molding method, a concave portion (not shown) is provided at a position corresponding to the GaP green LED element 5 at the time of this molding step, and a special shape is provided on an inner wall thereof.

That is, as shown in FIGS. 1a, 1b, 1c and 1d, concave portions 6 having a curvature are formed in a cross section parallel to the wiring board 2. FIG. 1a shows a perfect circle in cross section, FIG. 1b shows an ellipse in cross section, and FIG.
In FIG. 1 (d), the opposite arcs are shown, and each corner of the rectangular parallelepiped is
Are shown, and any of them is applicable. Thus, not only circles but also combinations of various figures as shown in the drawings may be used.

By the way, the integration of the wiring substrate 2 and the transparent molded body 3 is performed by thermocompression of a projection and a through hole formed relatively to the both.

〔The invention's effect〕

FIG. 3 shows the result of investigation of the effective illuminance distribution by taking the illuminance on the ordinate and the length of the photoelectric conversion element on the abscissa. Although the result that is superior to the photoelectric conversion element array is obtained, the definition of this illuminance is described below. The effective illuminance distribution is divided, the effective illuminance in each section is obtained, and the average value is obtained. Is the illuminance peak.

According to the above investigation results, the photoelectric conversion element array according to the present invention has an illuminance improved by about 10% as compared with the conventional photoelectric conversion element array, and the advantage of the transparent molded body having the concave portion having the curvature is apparent.

[Brief description of the drawings]

FIGS. 1a, 1b, 1c and 1d are cross-sectional views showing a part of a transparent molded body installed in a photoelectric conversion element array according to the present invention, FIG. 2 is a perspective view of this photoelectric conversion element array, and FIG. 4A and 4B are cross-sectional views each showing a part of a conventional example.

Claims (5)

(57) [Claims] 1. A wiring board, a plurality of photoelectric conversion elements arranged in a straight line on the wiring board, and the photoelectric conversion element at a position covering the photoelectric conversion elements and facing the photoelectric conversion elements. A transparent molded body provided with independent concave portions for reflecting the radiated light, wherein a cross section of the concave portions parallel to the surface of the wiring substrate has a closed curve shape. 2. The photoelectric conversion element array according to claim 1, wherein the cross section of the concave shape is a perfect circle. 3. The photoelectric conversion element array according to claim 1, wherein the cross section of the concave shape is an ellipse. 4. The photoelectric conversion element array according to claim 1, wherein the cross section of the concave shape is rectangular. 5. The photoelectric conversion element array according to claim 1, wherein a curvature is provided at a corner of a cross section of the concave shape.