JPH0719893B2 - Optical semiconductor device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical semiconductor device in which a photoelectric conversion element for converting incident light into an electric signal is sealed with a light transmissive resin.

[Description of Prior Art]

Conventionally, the photoelectric conversion device for converting incident light into an electric signal is the second one.
It is configured as shown in the figure.

That is, the photoelectric conversion element 1 is fixedly held on the photoelectric conversion element support member 2, wire-bonded to the predetermined positions of the photoelectric conversion element 1 and the lead terminal 2'using the ultrafine metal wire 3, and then the light transmission is performed. The outer shape is formed by molding using the resin 4. After that, the external lead-out portion 2 ″ of the lead terminal 2 ′ is cut to a required length and bent to a desired state to form an optical semiconductor device.

However, the conventional optical semiconductor device having the above structure has various problems as described below.

That is, (i) when the light receiving part of the photoelectric conversion element 1 is composed of a plurality of (n) light receiving parts, the light 6 having a uniform light flux is supplied to the n light receiving parts of the photoelectric conversion element 1. Is incident, the electric signals obtained from the n photoreceptors are
Where they all have to be at the same level, there is the problem that they are not at the same level in practice. In addition, in the case where light is made incident on one of the n light-receiving parts and light is not made incident on the other light-receiving parts, dark current is applied to the light-receiving parts which do not make light incident. However, there is also a problem that a large electric signal output is obtained.

Furthermore, (ii) when the surface 9 of the light transmissive resin 4 has a defect such as a scratch, the photoelectric conversion element 1 for the light incident from the defect.
There is a problem that the electric signal output from the light receiving section near the upper light reaching section 10 is reduced.

[Object of the Invention]

An object of the present invention is to provide an optical semiconductor device having excellent characteristics by overcoming the above-mentioned problems of the conventional optical semiconductor device described above.

That is, a main object of the present invention is to provide an optical semiconductor device sealed with a light transmissive resin, in which electric signals obtained from a plurality of light receiving parts constituting a photoelectric conversion element are uniform. To do.

Another object of the present invention is to reduce the electric signal from the light receiving part in an optical semiconductor device sealed with a light transmissive resin even if there are defects such as scratches on the surface of the light transmissive resin. An object is to provide an optical semiconductor device that does not have such a structure.

[Structure of Invention]

The present invention is to solve the problems in the above-mentioned conventional device, and after earnest research to achieve the object of the present invention,
It was found that the above-mentioned problems of the conventional device are caused by the following causes.

The cause of the above-mentioned problem will be described with reference to FIG.

That is, when the light ray 6 is incident on the light transmissive resin 4 and the photoelectric conversion element 4 at a right angle from the air layer 11, the surface 12 of the photoelectric conversion element 1 is
Then, the light is reflected and scattered. Light intensity reflected and scattered is the surface
It has an angle dependence, although it depends on the 12 materials and area. Some of the reflected scattered light escapes from the resin 4 to the air layer 11, and some of the reflected light is reflected at the interface between the air layer 11 and the resin 4.

According to Snell's law, total reflection occurs at an angle θ ₁ . θ ₁ is determined by the refractive indexes of the light transmissive resin 4 and the air layer 11.
For example, the light transmissive resin 4 and the air layer 11 each have a refractive index of 1.
When set to 5 and ₁ , θ ₁ is approximately 40 degrees and total reflection occurs when it becomes approximately 40 degrees or more. Therefore, the incident light amount A of the light receiving portion 5 of the photoelectric conversion element 1 is expressed by the following equation I.

A = (light amount of light beam 6) + (integral value of total reflected light amount of light ray forming θr (θr ≦ θ ₁ ) + (integral value of reflected light amount of light ray forming θr (θr <θ ₁ )) ... I Although the third time value of [theta] r is theta ₁ is less than the term reflected light of the formula I is a value that can be ignored very small, [theta] r is theta ₁
The amount of reflected light becomes large when the value is close to.

That is, the incident light amount of the light receiving portion 5 is the light amount of the light ray 6 and the incident light amount of light reflected from the vicinity of the circumference of a circle drawn with the radius of l ₁ centered on the light receiving portion 5 on the surface of the photoelectric conversion element 1 and outside the circle. In this case, since the latter unnecessary reflected light is incident, abnormal optical characteristics occur and the above-mentioned problems occur.

The present invention has been completed as a result of further research based on the above findings.

That is, in the optical semiconductor device of the present invention, the photoelectric conversion element is fixedly held on the photoelectric conversion element supporting member, and the element and the lead terminal are electrically connected via the ultrafine metal wire, and then the light transmissive resin is used. In the sealed optical semiconductor device, a member such as glass or a light-transmitting resin is adhered to at least the light-transmitting surface of the outer shape of the sealing body with the light-transmitting resin, or Is characterized by being adhered by different kinds of light transmitting resins.

The optical semiconductor device of the present invention includes the aspects described below.

One of the aspects is an optical semiconductor device having the following configuration.

That is, an optical semiconductor device in which a photoelectric conversion element and a thin wire connecting the photoelectric conversion element and a lead terminal are sealed with a light-transmissive resin, the member being made of glass or a light-transmissive resin. Is bonded to the surface of the sealing body, and the distance between the light transmitting surface of the member and the photoelectric conversion element is D, and the total reflection angle on the light transmitting surface is θ ₁ ,
It is characterized in that the light receiving portion of the photoelectric conversion element is located in a region within a circle drawn with a radius of 2 · D · tan θ ₁ on the surface of the photoelectric conversion element.

Another aspect is a focus detection device having the following configuration.

That is, in a focus detection device comprising an imaging lens and a distance measuring sensor, the distance measuring sensor comprises a photoelectric conversion element, a thin wire connecting the photoelectric conversion element and a lead terminal,
While sealing with a light transmissive resin, a member made of glass or a light transmissive resin is bonded to the surface of the sealing body, the light transmissive surface of the member and the photoelectric conversion element When the distance between them is D and the angle of total reflection on the light transmitting surface is θ, 2 on the surface of the photoelectric conversion element.
The light receiving portion of the photoelectric conversion element is located in an area within a circle drawn with the radius of D · tan θ ₁ .

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
The present invention is not limited thereby.

FIG. 1 is a schematic sectional view schematically showing one embodiment of an optical semiconductor device of the present invention. In FIG. 1, the same reference numerals as those in FIG. 2 described above indicate the same parts as in FIG. That is, the photoelectric conversion element 1 is fixedly held on the photoelectric conversion element support member 2, wire-bonded to the predetermined positions of the photoelectric conversion element 1 and the lead terminal 2'using the fine metal wire 3, and then the light-transmissive resin 4 is used. Then, the outer shape is formed by a molding method such as a transfer molding method. After that, the glass 7 is attached to at least the light transmitting surface of the molded body by using the light transmitting resin 8, and the light transmitting resin 8 is cured and adhered.

In the optical semiconductor device of the present invention shown in FIG. 1, the refractive indexes of the glass 7 and the light transmissive resins 8 and 4 are substantially the same, and d ₁ is from the surface of the light transmissive resin 4 to the sensor surface of the photoelectric conversion element 1. , And d ₂ is the sum of the thickness of the glass 7 and the thickness of the light transmissive resin 8, and when the light beam 6 is incident on the glass 7 and the photoelectric conversion element 1 at a right angle, θ ₁ follows Snell's law In the case of the conventional optical semiconductor device (d ₂ = 0), the amount A of light incident on the light receiving portion 5 of the photoelectric conversion element 1 is represented by the following formula II when the reflection angle is used.

A = (amount of light of light ray 6) + (sum of incident light amount of light reflected from the vicinity of the circumference of a circle drawn with 1 ₁ as a radius on the surface of the photoelectric conversion element and from the outside of the circle). In the case of the optical semiconductor device (d ₂ ≠ 0) of the present invention,
It is represented by the following formula III.

A = (amount of light of light ray 6) + (sum of incident light amount of light reflected from the vicinity of the circumference of a circle drawn with the radius of l ₂ on the surface of the photoelectric conversion element 1) ... III l ₁ = 2d ₁ tan θ ₁ l ₂ = 2 (d ₁ + d ₂ ) tan θ ₁ l ₂ −l ₁ = 2d ₂ tan θ ₁ (θ ₁ and l ₁ are constant). Therefore, d ₂ (= glass 7 thickness and light transmissive resin 8
The larger the value of l ₂ −l ₁ becomes, the smaller the area where the reflected light enters becomes and the less the influence of reflection becomes. Further, since the intensity of light is inversely proportional to the square of the optical path length, in the case of the optical semiconductor device of the present invention, the optical path length becomes long, so that the absolute value of the incident intensity of reflected light also decreases and the influence is reduced. That is, in order to reduce the influence of the reflected light, in order to reduce the influence of the reflected light from the portion other than the light receiving portion of the photoelectric conversion element 1, masking is performed so that light cannot reach the portion other than the light receiving portion. The thickness and shape of the glass 7 may be designed so that the light receiving portion of the glass 7 is within a circle drawn with a radius of approximately l ₂ . In addition, even if masking is performed, if light reaches other than the light receiving portion on the photoelectric conversion element 1 surface, or if any light receiving portion has to exist outside the circle drawn with the radius of approximately l ₂ , the influence is affected beforehand. The thickness and shape of the glass 7 may be designed by grasping the degree of

Further, when there is a defect such as a flaw on the surface 9 of the light-transmitting resin 4, the flaw is filled with the light-transmitting resin 8 having a refractive index almost equal to that of the light-transmitting resin 4, and the influence on the optical characteristics is reduced. .

In this example, the glass 7 is used.
A light transmissive resin may be used instead of the glass 7. Further, although the example in which the glass 7 is pasted with the light transmissive resin 8 is described, the glass 7 is simultaneously formed when the light transmissive resin 4 is molded by the transfer molding method or the like, and the glass 7 is formed by the light transmissive resin 4 itself. Can also be held by adhesion.

Next, the effect of the present invention will be described with reference to FIG. In the optical semiconductor device of the present invention, the greater d ₂ is, the less the influence of reflection is, and the longer the optical path length is, the smaller the absolute value of the reflected light amount is, which is further reduced. In the optical semiconductor device of the present invention, even if the surface 9 of the light transmissive resin 4 has a defect such as a flaw, the light transmissive resins 4 and 8 have substantially the same refractive index and are not affected by the optical characteristics. INDUSTRIAL APPLICABILITY The optical semiconductor device of the present invention is effective for a line sensor in which a photoelectric conversion element has a multi-divided light receiving surface such as a CCD, an area sensor, and other sensors that are severely affected by reflection.

The effect of improving the optical characteristics when the optical semiconductor device of the present invention is used as an autofocus sensor of a camera will be described with reference to FIGS.

FIG. 3 is a development view of an optical system when the optical semiconductor device of the present invention is used as an AF sensor of a camera. In the figure, reference numerals 13 to 18 respectively indicate parts constituting the focus detection device (AFu). That is, 13 is a visual field mask placed near the focus surface, and 14 is a visual field mask.
Is a field lens, 15 is a distance measuring light beam splitting mask having apertures 15a and 15b, 16 is a secondary imaging lens, and 16a and 16b are lens portions. Reference numeral 17 denotes a distance measuring sensor (optical semiconductor device of the present invention), which has a pair of line sensors 17a and 17b in which a large number of pixels are aligned.

Reference numerals 18a and 18b denote images of 13a projected by the lens portions 16a and 16b of the secondary imaging lens 16, respectively, and the sizes of 15a are determined so that the boundaries are exactly adjacent to each other. 14
Is a lens for effectively guiding the passed luminous flux to the distance measuring luminous flux splitting mask 15 and the secondary imaging lens 16.

Therefore, in this optical system, the light flux that has passed through the taking lens forms an image on 13 and further passes through the openings 15a and 15b, and the lens portion 16
The images are re-imaged in the line sensors 17a and 17b into 18a and 18b by a and 16b. Then, the relative position of the two images on the line sensors 17a and 17b is detected to determine the in-focus state.

The principle is shown in FIG. Letting Ea and Eb be the outputs of the images projected on the line sensors 17a and 17b, it is assumed that the distance S between the two images is set to a certain value S _{0 in the} focused state. When the taking lens is out of focus, S ≠
S ₀ , but to detect this, Ea and Eb are relatively
A method of bit-shifting and taking the correlation of two images is used.

If the image on 18a affects the image on 18a itself due to the above-mentioned reflection, or the image on 18b affects the image on 18b itself due to the above-mentioned reflection, or on 18a. Ea and Eb have the original subject brightness distribution when the image of 18 affects the image on 18b due to the reflection described above, or when the image on 18b affects the image on 18a due to the reflection described above. Since the shapes are different, the correlation calculation is performed using information different from the true subject information, and as a result, an error is generated in the detected focus information.

The use of the optical semiconductor device of the present invention reduces the influence of reflection and gives accurate focus information, which is particularly advantageous for AF.

[Brief description of drawings]

FIG. 1 is a schematic sectional view schematically showing an embodiment of an optical semiconductor device of the present invention, and FIG. 2 is a schematic sectional view schematically showing a conventional optical semiconductor device. FIG. 3 is an exploded view of an optical system when the optical semiconductor device of the present invention is used as an AF sensor of a camera, and FIG. 4 is a diagram for explaining its principle. 1 ... Photoelectric conversion element, 2 ... Photoelectric conversion element support member,
2 '... Lead terminal, 2' ... Lead-out portion of lead terminal, 3 ... Extra fine metal wire, 4 ... Light transmissive resin, 5 ... Photoreceptor of photoelectric conversion element, 6 ... Ray, 7 ...... Glass, 8
…… Light-transmitting resin, 9 …… Light-transmitting resin surface, 10 ……
Light reaching part, 11 ... Air layer, 12 ... Surface of light conversion element, 13
...... Field mask, 14 ...... Field lens, 15 ...... Distance measuring luminous flux splitting mask, 15a, 15b ...... Aperture, 16 ...... Secondary imaging lens, 16a, 16b ...... Lens section, 17 ...... Distance measuring Sensor, 17a, 17b ... Line sensor, 18a, 18b ... Projected image of 13a

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ichiro Onuki, 770 Shimonoge, Takatsu-ku, Kawasaki, Kanagawa Canon Inc., Tamagawa Plant (72) Inventor, Yasuo Suda 770, Shimonoge, Takatsu-ku, Kawasaki, Kanagawa At the Tamagawa Plant (72) Inventor Keishi Otaka At 770 Shimonoge, Takatsu-ku, Kawasaki City, Kanagawa Prefecture Canon Inc., Tamagawa Plant

Claims (2)

[Claims] 1. An optical semiconductor device in which a photoelectric conversion element and a thin wire connecting the photoelectric conversion element and a lead terminal are sealed with a light transmissive resin, which is made of glass or a light transmissive resin. The member consisting of is bonded to the surface of the sealing body,
When the distance between the light transmitting surface of the member and the photoelectric conversion element is D and the total reflection angle on the light transmitting surface is θ ₁ , 2 · D · tan θ ₁ is the radius on the surface of the photoelectric conversion element. An optical semiconductor device in which the light receiving portion of the photoelectric conversion element is located in a region within the circle drawn as above. 2. A focus detection device comprising an imaging lens and a distance measuring sensor, wherein the distance measuring sensor comprises a photoelectric conversion element, and a thin wire connecting the photoelectric conversion element and a lead terminal. Is sealed with a light-transmitting resin,
A member made of glass or a light-transmitting resin is attached to the surface of the sealing body, and the distance between the light-transmitting surface of the member and the photoelectric conversion element is D, and the total reflection angle on the light-transmitting surface is D. When θ, the focus detection device is characterized in that the light receiving portion of the photoelectric conversion element is located in a region within a circle drawn with a radius of 2D · tan θ ₁ on the surface of the photoelectric conversion element. .