JPH01196985A - Solid-state image pickup device - Google Patents

Abstract

PURPOSE:To prevent ghost or flair due to reflection on a read frame by setting the size of a solid-state image pickup element and a read frame or their mount position so that the reflected light made incident via the read frame and the upper face of the inside of the transparent resin is blocked on the side face of the solid-state image pickup element. CONSTITUTION:A sensor chip 1' of the solid-state image pickup element is mounted on a read frame 4', a prescribed wiring is applied by using a wire 3, and the entire part is sealed by using a package 2 of mold forming by a transparent resin. Then various dimensions and mount position such as height of side face of solid-state image pickup element 1', width of reflecting face on read frame 4' around image pickup element 1, are set so that the reflected light made incident from the outside and reflected in the upper face of the seal frame 2 made of the transparent resin and the surface of the read frame 4' and reaching the image pickup face on the solid-state image pickup element 1' is blocked in advance on the side face of the image pickup element 1'. Thus, ghost or flair due to reflection in the read frame 4' is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a solid-state image sensor sealed with a transparent resin or the like.

[Conventional technology]

2. Description of the Related Art Solid-state imaging devices have been widely used in imaging systems and other applications.

- Generally, the configurations of these solid-state image sensors are of the type shown in FIGS. 6 and 7, respectively, and are well known.

In the type shown in FIG. 6, for example, CO is placed on the lead frame 4.
A sensor chip 1 of a solid-state image sensor such as D is arranged,
It is connected to a predetermined portion by a wiring wire 3. The sensor chip 1, including its surface, is sealed with a package molded with transparent resin.

In the type shown in FIG. 7, the sensor chip 1 is placed on the lead frame 4 together with wiring wires 3, and a glass plate 5 is pasted on the surface of the sensor chip 1 with transparent acrylic resin or transparent silicone adhesive. A frame is molded around the frame using transparent or opaque resin. A conventional example of this type is, for example, Japanese Patent Laid-Open No. 186673/1983.

[Problem to be solved by the invention]

However, according to the conventional type of solid-state image sensing device as described above, when strong incident light P hits the periphery of the imaging area, a circular shape as shown by the symbol F is generated within the imaging area as shown in FIG. ghost of.

There is a problem in that flare occurs, which is a very serious drawback especially in two-dimensional imaging devices such as the one shown in the figure. Ghosts and flares that occur within the imaging area are caused by the incident light on the aluminum electrodes around the imaging area, the light-shielding aluminum layer for creating the black reference signal of the video signal, the lead frame for attaching the sensor chip, etc. It is thought that this is caused by reflection. Regarding reflections on the surface of the sensor chip, such as aluminum electrodes or light-shielding aluminum, it is conventional practice to form a dye layer on the top surface of the areas where these reflections occur, as is conventionally done, for example, in solid-state image sensors in ceramic packages. Measures were taken to reduce the reflectance. However, when looking at lead frames, for example, if a dye layer is applied to the lead frame alone, it cannot be used in the subsequent assembly of the sensor chip and lead frame because it deteriorates the conductivity of both. It is extremely difficult to apply dye to the surface of the lead frame after the lead frame is assembled, and the problems of ghost and flare caused by reflection on the lead frame remain unsolved.

[Means for Solving the Problems] The present invention has been made for the purpose of eliminating the above-mentioned drawbacks, and the present invention has been made with the aim of eliminating the above-mentioned drawbacks.
In a solid-state imaging device whose periphery is sealed with a transparent resin, when there is incident light from the outside, it enters the imaging area on the solid-state imaging device through the lead frame and the internal upper surface of the transparent resin. By setting the dimensions or mounting positions of the solid-state image sensor and the lead frame so that the reflected light that is reflected on the lead frame can be blocked by the side surface of the solid-state image sensor, the reflection of incident light on the lead frame can be prevented. This is designed to prevent ghosts and flares that occur when

Further, according to the present invention, in a solid-state imaging device in which a solid-state imaging device is disposed on a lead frame and the periphery thereof is sealed with transparent resin, a region with high reflectance on the lead frame is viewed from a side of the solid-state imaging device. The distance to the end face of the solid-state image sensor is L, and the height of the solid-state image sensor on the lead frame is T.
, where D is the distance from the imaging surface on the solid-state imaging device to the top surface of the transparent resin, and Ls is the distance from the end surface of the imaging surface to the side surface of the solid-state imaging device. As a result, ghosts occur on the imaging area due to reflection of incident light on the lead frame.
This is to prevent flare.

[Embodiment] Hereinafter, an embodiment of the solid-state imaging device according to the present invention will be described in detail with reference to the drawings.

FIG. 1(a) is a side sectional view of a solid-state image sensing device according to the present invention, and FIG. 1(b) is a partial plan view thereof.

Components that are the same as those of the conventional example shown in FIGS. 6 and 7 will be described using the same reference numerals.

A sensor chip 1 of a solid-state image sensor is mounted on a lead frame 4'.
', and after performing the prescribed wiring with the wire 3, the package 2 is molded with transparent resin.
The whole is sealed by. In the figure, T is the height of the sensor chip 1' from above the lead frame 4', and Lr is the distance between the end surface of the sensor chip 1' and the end surface of the lead frame 4'. Further, as shown in FIG. 1(b), when the sensor chip 1' is viewed from above, an imaging area (image area) 1'b is formed within the frame 1a of the sensor chip 1', and Ls is an image area t. It shows the distance between the end surface of 'b and the end surface of the sensor chip 1', that is, the width of the frame 1'a other than the image area of the sensor chip 1'.

Here, a ghost appears on the image area due to the reflected light on the lead frame 4' of the light incident on the imaging device.
The reason why flare etc. occurs will be analyzed using FIG. 2, which is an enlarged view of the portion indicated by A in FIG. 1.

In Figure 2, the distance from the end of the sensor chip 1' @ L
When a light beam is incident at position a on the lead frame 4' of r, a part of the light reflected by the lead frame 4' is blocked by the side surface of the sensor chip and does not reach the package surface, but another part I11 is The reflected light λ2 reaches the position on the surface of the transparent resin package, is reflected again toward the sensor chip 1', and enters the position C within the imaging area.

The intensity of light incident on the imaging area through such a path is as shown in FIG. In the figure, the vertical axis is the intensity of incident light within the imaging area, and the horizontal axis is the incident position a of light l incident on the periphery of the imaging area from outside the image sensor, and the reflection at the incident position a to position b on the package surface. The light rays 1. reflected from the light 11 onto the imaging area. is the distance between the incident position C and the incident position C.

As shown in the figure, the intensity of the light incident on the imaging area is determined by the distance from position a to position C as reflected light 11
Under conditions where the angle of incidence θ with respect to the package surface is less than the critical angle determined by Snell's law, there is little reflection (light ray U2) into the imaging area, so the incident angle θ is less than the critical angle determined by Snell's law. It suddenly increases at the distance lid where
becomes smaller in inverse proportion to the power of

FIG. 4 is a characteristic diagram showing the reflectance of the package surface with respect to the incident angle θ of the package surface, where the vertical axis shows the reflectance and the horizontal axis shows the incident angle θ. It can be seen that the reflectance changes significantly before and after the incident angle θ reaches the critical angle θ'.

As mentioned above, when strong light is incident around the imaging area,
As shown in FIG. 8, a false signal corresponding to the intensity of the light is generated in the solid-state image pickup device centered at the point of incidence L, and a circular ghost or flare having a radius equal to the distance l1llid is generated. This ghost has a dark inside of a circle with radius d.1. The outside becomes brighter, and it appears as if a circular shadow with radius d has appeared.

The range Lf of this flare is defined as the incident point a on the lead frame 4 of the light ray A from the end surface of the sensor chip 1 in FIG.
Lr is the distance from point a to the arrival point C of the reflected light on the imaging area; T is the height of the top surface of the sensor chip from the lead frame 4; and T is the distance from the imaging surface of the sensor chip to the package surface. The distance of Dl is further shown in Figure 1 (b
), if the distance between the outer shape of the sensor chip and the imaging area is Ls, then Lf=Li−Ls
. . . There is the relationship (2), and flare will occur in the range of width Lf on the imaging area.

Therefore, the size of the flare range Lf expressed by equation 0 is the width Ls of the frame 1a on the upper surface of the sensor chip 1.
If it is smaller, that is, Ls≧Lf
...... If it is set as follows, even if the internally reflected light reaches the sensor chip 1 based on the process described above due to strong incident light, it will be on the frame 1a and within the image area 1b. is not incident, and no ghost or flare occurs.

By substituting the 0 expression into the 0 expression and then substituting it into the 0 expression, the following 0 expression is obtained.

Ls≧□・Lr River... ■ In other words, when designing the mounting of the image sensor, the distance 11i between the outer shape of the sensor chip 1 and the end surface of the image area 1b is determined.
L s, end surface of sensor chip 1 and lead frame 4'
By determining the relationship between the distance Lr and the end face so as to satisfy Equation 0, ghost and flare can be prevented from occurring on the image area even if there is strong incident light around the image area and internal reflection occurs. I can do it.

FIG. 5 shows another embodiment of the invention. According to the first embodiment described above, the lead frame 4' designated Lr
The above explanation is applied to the area on the lead frame 4'' where the reflection occurs.

In other words, as mentioned in the explanation of the prior art, it is generally inappropriate to provide a dye layer on the lead frame 4'' because it deteriorates the conductivity, and it is also inappropriate to deposit the dye layer with high precision on the edge of the outer shape of the sensor chip. Although it is difficult to do so in terms of mounting accuracy, as long as the relationship of the above equation 0 of the present invention is satisfied, the sensor can be installed without cutting the size of the lead frame 4'' itself, as shown in FIG. Chip 1'
The dye layer 6 can be formed at a distance Lr or more from the side surface. In other words, as long as the dye is located at a certain distance from the sensor chip 1 and does not overlap the mounting position of the sensor chip 1, there is no problem at all even if the dye is shifted inward from Lr. It is possible to reduce the rate.

Especially when the dimensions of the lead frame 4'' cannot be changed due to other factors, or when the lead frame 4 of the sensor chip
This is an effective means in cases where the mounting dimensions cannot be set freely due to other conditions, such as when the distance 1iT from above cannot be set high, or when there are restrictions on the thickness D of the package 2.

〔Effect of the invention〕

As described above, according to the solid-state imaging device of the present invention, light enters from the outside, is reflected on the lead frame surface and the upper surface of the transparent resin sealing frame, and reaches the imaging surface on the solid-state imaging element. The dimensions and mounting position of each element, including the height of the side surface of the solid-state image sensor, the width of the reflective surface on the lead frame around the image sensor, etc., should be adjusted so that reflected light can be blocked on the side surface of the image sensor. With this setting, it is possible to prevent the occurrence of ghosts and flare within the imaging area by setting the dimensions at the time of manufacturing and assembling each component without using any special configuration, and the image quality is always faithful to the incident image. It is possible to perform high-quality imaging.

[Brief explanation of the drawing]

FIG. 1(a) is a side view showing a first embodiment of a solid-state imaging device according to the present invention, FIG. 1(b) is a partial plan view of the same, and FIG. 2 is a diagram showing the occurrence of ghosts and flares and details of the present invention. Figure 3 is a characteristic diagram showing the relationship between the intensity of incident light and the distance from the incident position; Figure 4 is a graph showing the angle of incidence and reflectance on the inner surface of a transparent resin package of a solid-state imaging device. FIG. 5 is a side view showing another embodiment of the solid-state imaging device according to the present invention; FIGS. 6 and 7 are side views showing an example of the conventional solid-state imaging device; FIG. 8 is a diagram showing ghosts and flares occurring on the imaging area. DESCRIPTION OF SYMBOLS 1...Solid-state image sensor (sensor chip), 2...Transparent resin package, 3...Wire 4.4', 4''...Lead frame, 5...Glass plate, 6...Dye Figure 4: W input target θ

Claims (4)

[Claims] (1) In a solid-state imaging device in which a solid-state imaging device is placed on a lead frame and the periphery thereof is sealed with a transparent resin, when there is incident light from the outside, the light is transmitted through the lead frame and the inner upper surface of the transparent resin. The dimensions or mounting positions of the solid-state image sensor and the lead frame are set so that reflected light entering an imaging area on the solid-state image sensor can be blocked by a side surface of the solid-state image sensor. solid-state imaging device. (2) In claim (1), the arrival position of the reflected light on the imaging surface of the solid-state image sensor is determined from a side surface of the solid-state image sensor to an end of a region with high reflectance on the lead frame. A solid-state imaging device characterized by being set according to the distance to. (3) Claim (1) is characterized in that the arrival position of the reflected light on the imaging surface of the solid-state image sensor is set by a height dimension of a side surface of the solid-state image sensor with respect to the lead frame. A solid-state imaging device. (4) In a solid-state imaging device in which a solid-state imaging device is arranged on a lead frame and its periphery is sealed with transparent resin, the distance from the side surface of the solid-state imaging device to the end face of the high reflectance region on the lead frame is The distance is L, the height of the solid-state imaging device on the lead frame is T, and the distance from the imaging surface on the solid-state imaging device to the top surface of the transparent resin is D.
, where Ls is a distance from an end surface of the imaging surface to a side surface of the solid-state imaging element, and a solid-state imaging device is mounted such that Ls≧D/T·Lr.