JPH07209610A - Resin sealed type solid-state image pickup element - Google Patents

Abstract

PURPOSE:To obtain the low-cost phase grating integrated type solid-state image pickup element which is suitable for mass-production by forming-phase type diffraction gratings which have optical low-pass effect on the surface of transparent resin covering the photodetection surface side of a CCD area sensor. CONSTITUTION:The CCD area sensor 2 is molded by having its entire peripheral surface sealed with the transparent resin, and image information of the CCD area sensor 2 is led out through a lead frame 3. The phase type diffraction gratings 1a which have the optical low-pass effect are provided on the top surface of the transparent resin 1 covering the photodetection surface 2a of the CCD area sensor 2. The diffraction gratings 1a are large enough to secure grating performance on the photodetection surface 2a of the CCD area sensor 2, and also formed at lower height for prevention against flaw. A light beam which is made incident through a photography optical system so that it is imaged on the photodetection surface 2a is separated by the phase type diffraction gratings 1a and reaches the photodetection surface 2a, thereby obtaining desired low-pass characteristics.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state image pickup device used for image pickup in a video camera, an electronic still camera or the like, and in particular, a resin encapsulation for sealing a CCD area sensor which is an image pickup device with a mold resin. The present invention relates to a static solid-state image sensor.

[0002]

2. Description of the Related Art Generally, in a camera using a solid-state image pickup device having a discrete pixel structure such as a CCD area sensor, image information of a subject is optically spatially sampled to obtain an output image. In this case, if the image information of the subject contains high spatial frequency components higher than the sampling frequency,
Many false color signals that the subject does not have are generated. For this reason, conventionally, an optical low-pass filter is arranged in a part of the photographing system to limit the high spatial frequency component of the subject.

As a means for limiting the high spatial frequency components of a subject, an optical low pass filter is arranged in a part of the photographing system. As an optical low-pass filter, a crystal filter utilizing birefringence such as a crystal plate is often used. However, in recent years, a phase diffraction grating type optical low-pass filter is becoming popular as an optical low-pass filter which replaces the crystal filter. However, although the phase diffraction grating type optical low-pass filter is less expensive than the crystal filter, it has the following problems.

When a phase diffraction grating is provided in a photographic optical system using a solid-state image sensor, as shown in FIGS. 6A and 6B, a CCD 61 and a phase diffraction grating 62, which are solid-state image sensors, are provided. There are a case (a) in which the photographing optical system 63 is interposed and a case (b) in which the photographing optical system 63 is not interposed.

In case (a), a lattice image is not generated in the image received by the solid-state image pickup device 61, but in case (b), a lattice image is generated due to the distance between the phase diffraction grating 62 and the CCD 61 light receiving surface. is there. In order to prevent the generation of a grating image in the image, the grating pitch of the phase diffraction grating 62 needs to be about twice the pixel pitch of the CCD 61 or less. In this case, the distance between the phase diffraction grating 62 and the CCD 61 light receiving surface is It gets quite short. Although this distance varies depending on the cross-sectional shape of the grating, the low-pass frequency, and the type of CCD, it is generally around 0.1 mm and 0.2 mm or less. Therefore, unless the phase diffraction grating 62 and the CCD 61 are integrated with each other, it is not possible to set such an interval.

On the other hand, in the case (a), since the photographing optical system 63 is provided between the CCD 61 and the phase diffraction grating 62, it is necessary to manufacture a dedicated phase dedicated grating for each lens, which means that parts are commonly used. It is disadvantageous in that it is difficult to construct the case (a) especially in a camera using a general-purpose lens of the standard such as C / Cs mount.
Since the phase diffraction grating 62 is incorporated in 63, there is a drawback that the structure of the lens barrel becomes complicated.

[0007]

In order to solve the above-mentioned problems, it has been proposed to integrate a phase diffraction grating filter and a solid-state image pickup device as disclosed in, for example, Japanese Patent Laid-Open No. 63-307423. ing. However, in all of these proposals, the phase diffraction grating filter is separate from the CCD package, and is incorporated later in a separate process. For this reason, alignment and mounting accuracy are required, and assembly costs as well as parts costs are not suitable for mass production, which is a factor of cost increase.

An object of the present invention is to provide a solid-state image pickup device integrated with a phase grating, which is suitable for mass production and minimizes cost increase.

[0009]

The above object is to provide a solid-state image sensor in which an area sensor is sealed with a transparent resin.
On the surface of the transparent resin that covers the light receiving surface side of the CD area sensor,
A resin-encapsulated solid-state imaging device (first invention) characterized by molding a phase-type diffraction grating having an optical low-pass effect, and a solid-state imaging device in which an area sensor is encapsulated with resin. The light-receiving side of the sensor is made of transparent resin and the back side is made of light-shielding resin. Two types are molded, and a phase type diffraction grating having an optical low pass effect is molded on the surface of the transparent resin part. This is achieved by a static solid-state imaging device (second invention).

In the preferred embodiments of the first and second inventions, it is further common that another transparent resin having optical characteristics different from that of the transparent resin is engaged with the diffraction grating on the surface of the diffraction grating. It is preferable that the integrally molded embodiment and either the transparent resin molded of the diffraction grating or the other transparent resin described above have a characteristic of absorbing infrared light.

[0011]

1 is a schematic sectional view showing an embodiment of the first invention of the present invention. The CCD area sensor 2 has a peripheral surface all of which is sealed with the transparent resin 1 and has a mold shape, and the lead frame 3 allows the image information of the CCD area sensor 2 to be taken out. And C
The phase type diffraction grating 1 having an optical low pass effect is formed on the surface of the transparent resin 1 which covers the light receiving surface 2a of the CD area sensor 2.
a is provided.

The diffraction grating 1a has a size sufficient to ensure the grating performance with respect to the light receiving surface 2a of the CCD area sensor 2, and is formed to be one step lower in order to prevent scratches and the like. The cross-sectional shape of the phase type diffraction grating 1a may be any waveform such as a sin wave, a trapezoidal wave, a rectangular wave, and a triangular wave, depending on the configuration of the CCD area sensor 2 and the setting method of the low-pass characteristic, and the grating direction and the number of directions. , Pitch, amplitude, etc. can be freely set as long as they can be processed. Figure 5
FIG. 4 is an MTF characteristic diagram showing the low pass characteristic of a phase grating filter having a rectangular wave-shaped cross section. The light beam that has passed through the photographing optical system and is incident on the light receiving surface 2a so as to form an image is separated by the phase type diffraction grating 1a and reaches the light receiving surface 2a, so that a desired low-pass characteristic is obtained.

With such a structure, a CCD having an extremely low cost optical low-pass effect can be provided.

FIG. 2 is a schematic sectional view showing an embodiment of the second invention of the present invention. The light receiving surface 2a side of the CCD area sensor 2 is made of a transparent resin 1, and the back surface side is made of a light-shielding resin 4.
A phase type diffraction grating 1a having an optical low-pass effect is provided on the surface of the transparent resin 1. Reference numeral 3 indicates a lead frame.

When the entire outer periphery of the CCD is made of transparent resin as in the embodiment shown in FIG. 1, light from other than the light receiving portion easily enters as stray light. All of these stray light are unnecessary light, and the stray light that has entered acts as a noise, and in order to prevent such a phenomenon in the embodiment of FIG. Therefore, it is necessary to block the light other than the light receiving surface, but the mechanism becomes slightly complicated.

Therefore, as shown in the embodiment of FIG. 2, if the light-shielding resin other than the front surface of the light-receiving surface 2a is molded in two kinds, a sufficient light-shielding effect can be obtained without paying special attention to the mechanism. In the embodiment shown in FIG. 2, the light-shielding resin is used except for the front surface of the light-receiving surface 2a. However, even if the light-shielding resin is only on the back surface or the range of the transparent resin is changed to some extent, a certain effect can be obtained. You can

The embodiment shown in FIG. 3 is further integrated with the surface of the diffraction grating 1a of the embodiment shown in FIG. 1 so that the transparent resin 1 and another transparent resin 5 having different optical characteristics are meshed with the diffraction grating 1a. It is molded. In the embodiment of FIG. 1 or 2, the surface of the phase diffraction grating 1a is exposed, so that there is a problem that scratches or stains easily occur.
In this embodiment, another transparent resin 5 is used to protect the above problems.

In the embodiment shown in FIG. 3, resin materials having different optical characteristics such as refractive index are combined between the two kinds of transparent resins 1 and 5, so that, for example, JP-A-52-101056 or As known from Kaihei 3-191319, it is possible to improve optical performance.

FIG. 3 shows an embodiment in which another transparent resin 5 is provided on the surface of the diffraction grating 1a of the embodiment shown in FIG. 1, but the surface of the diffraction grating 1a of the embodiment shown in FIG. Another transparent resin layer having a different optical characteristic from that of the transparent resin may be integrally formed so as to be engaged with the diffraction grating 1a. In this case, in addition to the effect of FIG. 3, the embodiment of FIG. It is also possible to obtain the light-shielding effect that it has.

In the embodiment shown in FIG. 4, another transparent resin 5 having an optical characteristic different from that of the transparent resin 1 is formed on the surface of the diffraction grating 1a of the embodiment shown in FIG. 1 or 2 (the drawing is shown in FIG. 1). Is further integrally molded so as to mesh with the diffraction grating 1a, and the phase type diffraction grating 5a is also formed on the light receiving surface side of the transparent resin 5 located outside.
Is provided. When setting the low-pass characteristic, the degree of freedom of the lattice is greater in two directions than in one direction. However, when the phase grating is manufactured by a mold and the mold is manufactured by cutting, there are cases where the grating can be set in only one direction on one surface. However, in the case of the configuration shown in FIG.
It is possible to set the directions of the grating in two directions, and good low-pass characteristics can be obtained.

In the embodiment described below, the transparent resin 1 in FIGS. 1 and 2 is a transparent resin having a characteristic of absorbing infrared light, and either the transparent resin 1 or 5 in FIG. 3 or 4 is used. Is a transparent resin having a characteristic of absorbing infrared light. With such a configuration, the CCD area sensor 2 can obtain an image signal at a light wavelength close to the luminosity factor.

[0022]

In the resin-sealed solid-state image sensor according to the present invention, the outer periphery of the CCD area sensor is integrally sealed with resin, so that the performance is stabilized and the life is extended by eliminating the influence of environmental conditions. In addition, since the transparent resin covering the front surface of the light receiving surface is molded with a phase type diffraction grating having an optical low pass effect, it is excellent in mass productivity and discrete image information can be obtained. Even in the above CCD, a good quality image signal can be obtained by preventing the generation of false color signals. Further, according to the second invention of the present invention, in addition to the above-mentioned effect, since the unnecessary light to be incident on the light receiving portion is blocked, a high-quality image signal with less noise can be obtained. .

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the first invention of the present invention.

FIG. 2 is a schematic sectional view showing an embodiment of the second invention of the present invention.

FIG. 3 is a schematic sectional view showing another embodiment of the present invention.

FIG. 4 is a schematic sectional view showing still another embodiment of the present invention.

FIG. 5 is an MTF showing a low pass characteristic of a phase grating filter.
It is a characteristic diagram.

FIG. 6 is an explanatory diagram showing an arrangement relationship of diffraction gratings.

[Explanation of symbols]

 1,5 Transparent resin 1a, 5a Diffraction grating 2 CCD area sensor 2a Light receiving surface 3 Lead frame 4 Light blocking resin

Claims (6)

[Claims] 1. In a solid-state image sensor in which an area sensor is sealed with a transparent resin, a phase type diffraction grating having an optical low pass effect is formed on the surface of the transparent resin covering the light receiving surface side of the CCD area sensor. A resin-encapsulated solid-state image sensor characterized by the above. 2. The surface of the diffraction grating is further integrally molded with another transparent resin having optical characteristics different from that of the transparent resin so as to mesh with the diffraction grating.
Resin-encapsulated solid-state image sensor. 3. The resin-sealed mold according to claim 1, wherein either the transparent resin molded with the diffraction grating or the other transparent resin has a property of absorbing infrared light. Solid-state image sensor. 4. A solid-state imaging device comprising an area sensor sealed with resin, wherein the light receiving surface side of the CCD area sensor is made of transparent resin and the back side is made of light-shielding resin. A resin-encapsulated solid-state imaging device, characterized in that a phase-type diffraction grating having an optical low-pass effect is molded. 5. The surface of the diffraction grating is further integrally formed with another transparent resin having optical characteristics different from that of the transparent resin so as to be engaged with the diffraction grating.
Resin-encapsulated solid-state image sensor. 6. The resin-sealed mold according to claim 4, wherein either the transparent resin molded with the diffraction grating or the other transparent resin has a property of absorbing infrared light. Solid-state image sensor.