JPH05206487A - Light receiving components - Google Patents

Abstract

PURPOSE:To provide a light receiving component which is provided with an excellent condensation characteristic which condenses much light and an electromagnetic noise cutoff effect which cuts off electromagnetic noise from different equipment in light receiving components used for an infrared remote controller or optical space transmission or the like. CONSTITUTION:A plano-convex lens 1 and a light receiving device installed on the flat portion of the lens 1 in such a fashion that its central axis may agree with that of the lens 1 are provided. What is more, a light receiving component is designed so that the conduction side of a transparent electrode 4 may come to the side of the light receiving device between the plano-convex lens 1 and a pin photodiode 5 which serves as the light receiving device. A shielding board 6 is connected to the transparent electrode 4 so as to condense much light to the light receiving component. Moreover, the light receiving component can be shielded electromagnetically.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light receiving part used for infrared remote control and optical space transmission.

[0002]

2. Description of the Related Art A conventional light receiving component will be described with reference to FIG.

FIG. 6 shows the structure of a conventional light receiving component and an optical space transmission device using the light receiving component.

In the figure, 31 is an LED, 32 is a light receiving module, 33 is an amplifier, 34 is a modulator, 35 is a sound source, 36 is a pin photodiode, 37 is a preamplifier,
39 is a demodulator, 40 is an amplifier, 41 is a speaker, and 42 is an optical signal.

The operation of the optical space transmission device using the light receiving component constructed as described above will be described below.

The audio signal output from the sound source 35 is FM-modulated by the modulator 34 and then amplified by the amplifier 33. The amplified audio signal is sent to the LED 31 of the light emitting module 32.
Is converted into an optical signal and output as an optical signal 42. The optical signal 42 is received by the pin photodiode 36, converted into an electric signal, and then amplified by the preamplifier 37. Since the amplified signal is FM-modulated, it is demodulated by the demodulator 39 and is returned to the voice signal. Further, the audio signal is amplified by the amplifier 40 and output as sound from the speaker 41. In this way, an audio signal can be converted into an optical signal and transmitted.

[0007]

However, in the above-mentioned conventional configuration, since the light is received only by the pin photodiode 36, the amount of light received becomes small when the distance between the transmitting side and the receiving side becomes large, and the transmission distance is reduced. I can't stay long. Further, since the pin photodiode 36 is easily affected by electromagnetic noise, electromagnetic noise generated from a personal computer when a digital device such as a personal computer is nearby is generated by the pin photodiode 3.
There was a problem in that the sound quality transmitted upon entering 6 was deteriorated.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a light-receiving component having a large light-collecting ability and an electromagnetic shield effect.

[0009]

In order to achieve this object, the light receiving component of the present invention comprises a convex plano lens and a light receiving element whose central axis coincides with the flat part of the convex plano lens. The configuration is such that the conductive surface of the transparent electrode is located between the lens and the light receiving element on the light receiving element side.

[0010]

With this structure, a large amount of light can be condensed on the light receiving element due to the light condensing effect of the lens.
Further, the light transmitting element and the electromagnetic shield effect of the transparent electrode can block the influence of electromagnetic noise on the light receiving element.

[0011]

EXAMPLE An example of the light receiving component of the present invention will be described below.
This will be described with reference to FIG. In FIG. 1, 1 is a convex plano lens,
2 is a transparent electrode substrate, 3 is a transparent electrode film, 4 is a transparent electrode,
Reference numeral 5 is a pin photodiode which is a light receiving element, 6 is a shield plate made of metal, 7 is a printed circuit board, 8 is a conductive resin, and 9 is a terminal of the light receiving element. The convex plano lens 1 is made of transparent acrylic resin, and in this embodiment, the radius of curvature R is 7 mm and the height H is 12 mm, and H / 2R =
It is 0.857. As the substrate 2 of the transparent electrode 4, one having a refractive index close to that of acrylic resin is used.
Was formed by the sputtering method. Since the refractive index of the substrate 2 and the convex plano lens 1 are very close to each other, there is almost no reflection on this adhesive surface. The pin photodiode 5 is bonded and fixed so that its central axis coincides with the central axis of the convex plano lens 1. Further, the transparent electrode film 3 of the transparent electrode 4 between the convex plano lens 1 and the pin photodiode 5 and the shield plate 6 are adhered with a conductive double-sided tape, and the pin photodiode 5 has its terminal 9 fixed to the printed board. There is.

With respect to the light receiving component constructed as described above,
The operation will be described with reference to FIG. First, the convex plano lens 1
When light parallel to is incident on the pin photodiode 5, the light is condensed and enters the pin photodiode 5. As shown in FIG. 2, the radius of curvature R
= 7 mm and the height H12 mm of the plano-convex lens 1 has a magnification and directivity of about 6 times and a half-value angle of 23 degrees as compared with the case where no lens is provided. Furthermore, the height of the lens is increased and H = 1.
When it is 3 (mm) (H / 2R = 0.928), the magnification is about 10 times and the half-value angle of the directivity angle is 15 degrees.

The substrate 2 of the transparent electrode 4 is a convex plano lens 1
Since it is very close to the refractive index of the acrylic resin that constitutes
When the substrate 2 is used by being bonded to the convex plano lens 1, there is almost no optical loss in this portion, and the amount of light lost by passing through the transparent electrode 4 is about 5%. The seal resistance of the transparent electrode film 3 is relatively small as 70Ω, and since the conductive double-sided tape 8 makes the transparent electrode 4 and the shield plate 6 electrically conductive, even if electromagnetic noise is incident on the pin photodiode 5 along with light. The transparent electrode 4 and the metal shield plate 6 block electromagnetic noise.

As described above, in the light receiving element according to the present embodiment, the pin photodiode 5 is provided at the center of the plane portion of the convex plano lens 1 through the transparent electrode 4, and the transparent electrode film 3 of this transparent electrode 4 is a pin. With the configuration in which the transparent electrode film 3 is in contact with the photodiode 5 and the transparent electrode film 3 is joined to the shield 6 plate, it is possible to easily design a lens having a light-condensing effect and directional characteristics most suitable for the purpose, and at the same time, to shield the electromagnetic shield. The effect will be obtained.

A second embodiment of the present invention will be described below with reference to the drawings. FIG. 3 is a sectional view of the configuration of a light receiving element showing a second embodiment of the present invention. In FIG. 3, 10
Numerals 12 to 12 are light receiving parts formed of a convex flat lens, a transparent electrode and a light receiving element, 13 is a cut portion of the lens, 14 to 16 are connection terminals of the light receiving element, and others are the same as those in the first embodiment.
The difference from the configuration of FIG. 1 is that three light receiving elements are tilted by 45 degrees and they are fixed on one shield plate 6,
The point is that the end of the flat portion of the convex plano lens is cut obliquely at an angle of 45 degrees. In the light receiving components 10 to 12, the connection terminals 14 to 16 of the light receiving element are fixed to the printed circuit board 7 by soldering.

The operation of the light receiving element having the same structure as described above will be described with reference to FIGS. 4 and 5. 2 in FIG.
1 is an LED, 22a to 24 are lights, 25 is an obstacle, 26
a, 26b are walls, 27a, 27b are reflected lights, 28a-2
Reference numeral 8c is a light receiving component, and 29a to 29c are light receiving elements. Now, as shown in FIG. 4, the light 2 emitted from the LED 21
3 goes straight as a light 24 when there is no obstacle 25,
The light is incident on the light receiving component 28a, and FIG.
8A to 28c show the directional characteristics of the light receiving components and the direct light, which indicate the light receiving amounts of the pin photodiodes 29a to 29c and the total light receiving amounts when the entire 8a to 28c are rotated by ± 90 degrees.

Further, the LED 21 and the light receiving elements 28a to 28 are provided.
When the obstacle 25 is placed between c as shown in FIG. 4, the light 24, which is direct light, is blocked, but the lights 22a and 22b go straight and are reflected by the walls 26a and 26b, and the light 27a and 27b.
b, which is incident on the light receiving elements 28b and 28c. FIG. 5B shows the light receiving characteristic of the reflected light when there is only the wall 26a, and shows the light receiving amount of the pin photodiodes 29a to 29c when the entire light receiving elements 28a to 28c are rotated by ± 90 degrees. As described above, the light receiving element 2
By arranging 9b and 29c at an angle of 45 degrees, the reflected light can be received even if the direct light from the LED 21 is blocked.

Incidentally, the three light receiving components 10 to 10 in FIG.
Since 12 are fixed to the shield plate 6a made of one trapezoidal metal with the conductive double-sided tape 17, the pin photodiodes and the terminals 15 to 16 provided on the light receiving components 10 to 12 are electromagnetically shielded as a whole. It Further, since the end portions 13 of the lenses of the light receiving components 11 and 12 are cut, the lenses can be easily mounted without hitting the shield plate 6a.

In the first embodiment, the shield plate 6 is a metal shield plate, but the shield plate 6 may be a conductive resin or a resin metal-plated to have conductivity. Further, although the conductive resin 8 is the conductive double-sided tape, it goes without saying that the conductive resin 8 may be a thermocompression-bonding conductive resin or a silver paste. In the second embodiment, the shield plate 6 is a trapezoidal metal plate, but the shield plate 6 may have any shape as long as it can fix the three light-receiving components by inclining them by 45 degrees. You can use what you have done.

[0020]

As described above, the present invention comprises a convex plano lens and
A pin photodiode is provided on the flat surface of this convex flat lens with its central axis aligned, and the light receiving component is configured so that the conductive surface of the transparent electrode is on the pin photodiode side between this convex flat lens and the pin photodiode. The transparent electrode
By adopting a configuration in which the sheets are connected by metal, it is possible to improve light condensing characteristics and prevent electromagnetic noise. By using the convex plano lens, the transparent electrode and the pin photodiode on the flat surface can be easily fixed by adhesion or the like. Further, it is possible to realize an excellent light receiving component that also has an effect that the converging magnification and the directivity angle characteristic can be optimized by changing the height of the lens.

[Brief description of drawings]

FIG. 1 is a sectional view showing the configuration of an embodiment of a light receiving component of the present invention.

FIG. 2 is a diagram showing the optical characteristics.

FIG. 3 is a sectional view showing the structure of a light receiving component according to the second embodiment.

FIG. 4 is a side view showing an arrangement configuration of the light receiving component in use in the second embodiment.

FIG. 5 is a diagram showing optical characteristics of a light receiving component according to the second embodiment of the present invention (a) A diagram showing directivity characteristics of direct light (b) A diagram showing directivity characteristics of reflected light

FIG. 6 is a diagram showing a conventional light receiving component and a signal transmission system of an optical transmission device using the same.

[Explanation of symbols]

 1 Convex flat lens 4 Transparent electrode 5 Pin photodiode 6 Shield plate

Claims (3)

[Claims] 1. A light receiving component comprising a convex plano lens and a light receiving element provided on a plane portion of the convex plano lens via a transparent electrode having its central axis aligned. 2. The light receiving component according to claim 1, wherein the transparent electrode is electrically conductive only on one side, and the conductive surface is in contact with the light receiving element. 3. The light receiving component according to claim 1, wherein the convex plano lens and the substrate of the transparent electrode are made of resin, and the refractive index thereof is substantially the same as that of the convex plano lens.