JPH04196363A - Light emitting/receiving device - Google Patents

Abstract

PURPOSE:To dispense with a light reflective means externally provided, to make the photodetective device miniature as a whole, and to enable an optical path changing means to be easily set constant without fluctuation by a method wherein a light reflecting part is provided to a molded case itself. CONSTITUTION:A light emitting/receiving element is molded with synthetic resin into a packaged light emitting/receiving device, where at least a part which serves as an optical path is formed of a transparent resin 6, and a part 10 which is so formed as to change the path of incident light is provided. That is, a light reflective part is provided to the molded package of a light emitting/ receiving device in one piece. By this setup, a light path changing means is not required to be externally provided, the device can be formed small in size as a whole, and an optical path changing means can be easily set constant without fluctuation.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to the shape of a molded resin package for a light receiving/emitting device.

(Prior Art) Examples of shapes of conventional light-receiving and emitting devices are shown in FIGS. 2 and 3, and the light-receiving device will be mainly described below.

The shape shown in Fig. 1 is extremely common, and as is well known, the light receiving element (chip) 3 is molded and packaged with transparent resin 1 (at least the optical path part), and the leads 2 are arranged to exit outside. It is a provision. As can be seen from Fig. 711), the light is received from above.

Therefore, conventionally, when it is desired to process light from the lateral direction due to constraints such as mounting, a mirror 4 is provided on top of the device as shown in Fig. 3 (usually installed at an angle of 45 degrees), or as shown in Fig. 4. A method is adopted in which an optical fiber 5 is provided to input light.

(Problems to be Solved by the Invention) However, as described above, the method using mirrors and optical fibers requires a space to mount them, making it impossible to reduce the size of the entire device.

Furthermore, it is difficult to determine the position of a mirror, optical fiber, etc. when it is fixed, and the more the mirror or optical fiber is deviated, the problem arises that insufficient light is input to the light receiving section.

(Means for Solving the Problems) As described above, the present invention has the disadvantage that the device as a whole cannot be miniaturized because the means for changing the path of light is provided externally, and its setting is difficult. As a means of solving this problem, we have developed a molded package made of transparent resin.
A light-reflecting portion is provided on the upper surface of the light-receiving portion or the light-emitting portion and is integrally molded.

(Function) As described above, in the present invention, since the molded package itself is provided with a portion that reflects light, there is no need to provide a light reflecting means outside the device, and the entire device can be miniaturized. It is easily possible to keep the settings of the changing means constant without variation.

(Embodiment) FIG. 1 is an external view of a first embodiment of the present invention, and FIG. 5 is a cross-sectional view thereof, and the following description will be made, but as in the conventional description section, the main focus will be on the light receiving device. Although this is a tedious point, it will be understood that no particular explanation is required in the case of a light emitting device, since the basic principle remains the same except that the optical path is reversed.

As shown in the cross-sectional view of FIG. 5, inside the mold package, the light receiving chip 3 is placed on the bonding frame 9, as in the conventional case, and molded so that the leads 2 are exposed to the outside as shown in FIG.

This embodiment differs from the conventional one in the shape of its mold package. This is because a portion 10 for changing the optical path is provided as shown in FIGS. 1 and 5. That is, the shape of the upper part of the light-receiving chip 3 is such that light from the lateral direction is reflected and the light is input to the chip 3. Of course, at least the portion that is exposed to the optical path is made of transparent resin.

In the first embodiment, as shown in FIGS. 1 and 5, the light reflecting portion has a straight line shape 10 with an inclination angle of 45°. In other words, it has a shape that allows light to enter the light-receiving chip 3 from the side. Furthermore, in this embodiment, red and infrared light were used as input light, so the mold resin (transparent resin) 6 had a maximum light transmittance for light with a wavelength of 850 nm and a refractive index. Although a resin with n=1.52 was used, such a resin can be realized by a conventionally known transfer mold resin.

Incidentally, when media with different refractive indexes are in contact with each other, the conditions for light to be refracted and travel therethrough are given by the following equation using Snell's law Qll.

nz /rl+ =COSO2/cosθ1n
,: B refractive index of medium, nz:, refractive index of medium, θ1
, θ, A, B refraction angle in medium.

This relationship is shown in FIG.

Furthermore, the incident angle O at which the light is totally reflected at the boundary between media B and A only needs to satisfy θ<cos-' (nz/n+). Therefore, in this example, the refractive index of air is 1, and the transparent resin is 6.
Since the refractive index of is 1.52, it is sufficient that θ<cos-'(1/1.52)"F48-8 degrees for total reflection. The relationship is shown in FIG.

Under the above conditions, a mold package was formed using transparent resin in the shape described above, as shown in Figure 1.
FIG. With such a shape, light from the lateral direction is totally reflected by the reflection section 10 and input to the light receiving chip 3.

In addition, as a second embodiment of the present invention, as shown in FIG. 8, if the reflecting part 10 is made into an aspherical shape and is formed to satisfy the conditions for total reflection, the light input to the light receiving chip 3 can be Light can be focused. When the beam diameter of the light is 2 mmΦ and the light receiving area of the light receiving chip 3 is 1 mmΦ, the beam diameter is reduced by 1/
What is necessary is to set the shape of the reflection section 10 so that the light is focused on 2.

(Effects of the Invention) As explained above, in the present invention, the light reflecting section is integrated into the shape of the molded package of the light receiving and emitting device, so there is no need to provide an external means for changing the optical path.
The entire device can be made smaller, and the setting of the optical path changing means can be easily made constant without variations.

[Brief explanation of the drawing]

Figure 1 is an external view of the first embodiment of the present invention, Figures 2 to 4 are configuration diagrams of conventional examples 1.2.3, and Figure 5 is a cross section of the first embodiment of the present invention. Figure 6 is an explanatory diagram of refraction of light, Figure 7
The figure is an explanatory diagram of light reflection, and FIG. 8 is a sectional view of a second embodiment of the present invention. 1......Mold resin, 2...
・・・・・・・・・Lead, 3・・・・・・・・・Light receiving chip, 6・・・・・・・・・Transparent resin, 10・・・・・・
・・・・・・Reflector.

Claims (1)

[Claims] The shape of the molded package of the light receiving and emitting device is a package in which the light receiving and emitting elements are molded and packaged with synthetic resin.
A light receiving/emitting device characterized in that at least a portion corresponding to an optical path is made of a transparent resin, and a portion shaped to change an incident optical path is provided.