JP2553656Y2 - Optical semiconductor device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical semiconductor device used for various electronic devices, and more particularly to a light receiving device for a remote control which requires a wide directivity, high sensitivity and resistance to disturbance light.

[0002]

2. Description of the Related Art As shown in FIG.
The entire light receiving chip (optical semiconductor element) 1 integrated with the C circuit is molded with a visible light cut resin (infrared transmitting black resin), and the light is focused on the photodiode portion.
The lens 3 is provided on the upper part of the mold body 2.

Recently, a remote control device using light (hereinafter referred to as a remote control) has been used for various electronic devices.
R, TV, CD (boombox, component) air conditioner, camera, etc., and the environment in which it is used is various. In these environments, as ambient light, there are 50/60 Hz fluorescent lamps, inverter fluorescent lamps, and incandescent lamps indoors, and there is sunlight outdoors, and the ambient environment surrounding the remote control is flooded with ambient light.

[0004] Under these disturbance lights, with the widespread use of large-sized TVs, video cameras, and the like, there is an increasing demand for a longer reception distance and a wider directional angle.

[0005]

In a conventional light receiving device using an optical semiconductor element, in order to improve the receiving distance, a lens diameter is increased and an area for receiving signal light to be condensed is increased. , To increase the receiving distance by increasing the amount of signal light incident on the light receiving chip,
As the lens diameter is increased, the transmittance of light by the resin is reduced, the expected amount of incident light cannot be obtained, and it is difficult to increase the receiving distance.

FIG. 3 schematically shows a model in which the diameter of the lens is increased in order to improve the light collecting property. In this FIG.
For simplicity, it is assumed that all light incident on the lens is collected on the light receiving chip 1.

[0007] The lens diameter is increased by a times for light collection. FIG.
Then, the lens radius of A is r, and ar is B as in B. Further, the attenuation rate per 1 mm of the visible light cut resin is represented by α _O.

When all the light receiving chips are molded with visible light cutting resin, (D ₁ and d ₂ are distances from the lens center to the light receiving chip).

The incident light on the light receiving chip is

[0010]

(Equation 1)

[0011] As described above, the signal light incident on the light receiving chip is attenuated by _{α O r (a-1)} / 1-α term an amount corresponding mold resin _O (r + d _1).

[0012] Calculating the incident light amount as

[0013]

(Equation 2)

Thus, it can be seen that by increasing the lens diameter, only 55% of the increased incident area reaches the light receiving chip.

Further, when an aspherical lens is used to obtain a wide directivity angle characteristic, if the lens diameter is large, the signal light on the optical axis and the case where the incident angle (directivity angle) is applied to the resin are different. When the thickness changes, the transmittance differs, and the transmittance of incident light having an incident angle (directivity angle) decreases. For this reason, wide directivity angle characteristics may not be improved in some cases.

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide an optical semiconductor device capable of controlling a reduction in transmittance, improving a receiving distance characteristic and obtaining a wide directivity characteristic.

[0017]

Means for Solving the Problems According to the present invention, when a lens is formed with a mold resin, the thickness of a visible light cut resin portion is made uniform so that an unnecessary thickness is prevented. A lens 11 is formed on a first molded body 10 in which the light receiving chip is molded with a transparent light-transmitting resin, and is uniformly formed on the lens 11 of the first molded body 10 so as to surround the entire first molded body 10. The thickness of the second molded body 13 is made of a transparent resin that cuts visible light.
Is formed.

[0018]

In the above-mentioned means for solving the above problems, as shown in FIG. 2, in the case of a light receiving device in which the thickness of the visible light cutting resin is made uniform from the lens surface, The thickness of the visible light cut resin portion effects of attenuation of the incident light exits and D _3, the transparent resin portion is assumed that there is no attenuation as an ideal transparent.

The light incident on the light receiving chip is

[0020]

(Equation 3)

As described above, since the attenuation by the visible light cut resin is constant, the amount of signal light can be obtained as expected, and the reception distance characteristics can be improved.

Also, in order to increase the directivity angle, in the case of an aspherical lens (for example, an elliptical lens), the thickness of the mold resin portion changes between the optical path on the optical axis and the optical path having the directivity angle.
In the case of an elliptical lens for widening the directivity angle, if the angle of incidence increases, the thickness of the resin increases, the amount of attenuation increases, and the amount of light incident on the light-receiving chip may be reduced. By making the thickness of the resin molded body 13 uniform, the change in the attenuation due to the directional angle is improved, and the directional angle characteristics are improved.

[0023]

FIG. 1 is a sectional view of an optical semiconductor device showing an embodiment of the present invention, and FIG. 2 is a conceptual diagram showing a lens focusing characteristic of the optical semiconductor device according to the present invention.

As shown in FIG. 1, in a light receiving device as an optical semiconductor device, a light receiving element 9 directly bonded on a lead frame 8 is transfer-molded with a transparent light transmitting resin to form a primary molded body 10. The first lens 11 is formed on the upper part of the mold body 10. Further, transfer molding is performed again on these with a transparent resin that cuts off visible light to form a second molded body 13. In the second mold body 13, a second lens 14 having the same optical axis is formed on the upper surface of the transparent resin lens 11 with a visible light cut resin so as to have a uniform thickness.

If the thickness of the visible light cut resin is controlled by performing the above-mentioned double transfer molding so that the visible light cut resin is made uniform, noise is reduced by the visible light cut resin against disturbance light around the remote controller.

Further, since the second lens 14 does not have an unnecessary thickness, the attenuation of the signal light is limited, and the light collecting property can be improved. Further, since the thickness can be made uniform with respect to the directional angle, a wider directional angle can be obtained.

It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that many modifications and changes can be made to the above-described embodiment within the scope of the present invention.

For example, in the above embodiment, the light receiving device has been described. However, the present invention is not limited to this, and it is needless to say that the present invention can be applied to other optical semiconductor devices.

[0029]

[Effects of the Invention] As is clear from the above description, according to the present invention, the thickness of the visible light cut resin is controlled and uniform, so that the visible light can be cut against disturbance light around the remote controller. The noise can be reduced by the resin, and since the second lens does not have an unnecessary thickness, the attenuation of the signal light is limited, the light collecting property can be improved, and the thickness can be made uniform with respect to the directional angle. Therefore, there is an excellent effect that a wide directivity angle can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of an optical semiconductor device showing an embodiment of the present invention.

FIG. 2 is a conceptual diagram showing a lens focusing property of the optical semiconductor device according to the present invention.

FIG. 3 is a schematic view of a conventional optical semiconductor device showing a lens diameter, a light collecting property, and an attenuation property due to a resin with respect to a lens light collecting property.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 light receiving chip 2 molded body 3 lens 8 lead frame 9 light receiving element 10 first molded body 11 first lens 13 second molded body 14 second lens

Claims (1)

(57) [Scope of request for utility model registration] An optical semiconductor device is molded with a translucent resin to form a primary molded body, a first lens is formed on the primary molded body, and the primary molded body is molded with a visible light cut resin. A second lens body is formed on the secondary mold body, the second lens covering the outside of the first lens with a uniform thickness on the same optical axis as the primary mold body. Optical semiconductor device.