JPH06308430A - Image pickup device - Google Patents

Abstract

PURPOSE:To eliminate need for aligning an image pickup element and an optical low-pass filter when they are assembled and to prevent the positional deviation thereof caused by external force from occurring as for an image pickup device provided with the optical low-pass filter for suppressing the generation of a spurious signal by dispersing incident light. CONSTITUTION:Photoelectrical conversion elements 2 are two-dimensionally arrayed on the image pickup element 1 such as a CCD. On the surface of the element 1, a substrate 4 formed of a transparent material is integrally joined. On the surface of the substrate 4, the optical low-pass filter 5A is formed. The filter 5A is constituted so that light 6 made incident on one element 2 is diffracted and made incident also on the peripheral elements 2. Besides, it is constituted of a two-dimensional diffraction grating having a recessed and projecting cross section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup device. In particular, the present invention relates to an image pickup device including an image pickup element and an optical low-pass filter, which is used in a video camera, an electronic camera, or the like.

[0002]

2. Description of the Related Art Generally, an image pickup device such as a video camera is
Incident light is sampled by a plurality of photoelectric conversion elements arranged at regular intervals. In this case, there is a condenser lens for condensing the incident light on the photoelectric conversion element to increase the sensitivity, and an optical filter for preventing the generation of false signals.

As an image pickup apparatus in which a condenser lens and an optical filter having such a function are provided in an image pickup element, there is one disclosed in Japanese Patent Application Laid-Open No. 4-70802. In this image pickup device, for example, an optical filter substrate having a convex lens-shaped condensing lens portion provided on a surface facing the image pickup element and a concave lens-shaped optical filter portion provided on the other surface is provided at a predetermined distance from the image pickup element. The optical filter portion diffuses light corresponding to one pitch of the photoelectric conversion elements so that the light is incident on a plurality of photoelectric conversion elements, and the condenser lens portion collects the incident light on the photoelectric conversion elements. I am letting you.

[0004]

However, in the above-mentioned conventional image pickup apparatus, the image pickup element in which the photoelectric conversion elements are arranged and the optical filter substrate having the optical filter portion are separate bodies, and are individual components. Was there. Since the photoelectric conversion elements forming the image pickup device are arranged at a minute pitch of several microns, an optical filter substrate is attached to the image pickup device to convert light corresponding to one pitch of the photoelectric conversion device into a plurality of photoelectric conversions at predetermined positions. When the light is made incident on the device, high accuracy is required for the alignment between the optical filter substrate and the photoelectric conversion device, which makes assembly difficult. In particular, it was difficult to align the optical filter substrate and the image sensor in the optical axis direction.

Therefore, if the image pickup device and the optical filter substrate are separate, highly accurate alignment is required for each product, and high assembly precision is required. As a result, there is a problem that the product cost is high. In addition, if the image sensor and the optical filter substrate are separate,
If the mutual positions are displaced by an external force, there is a risk that the optical filter substrate will not perform its function.

The present invention has been made in view of the above-mentioned drawbacks of the conventional example, and in an image pickup device provided with an optical filter for dispersing incident light and suppressing generation of spurious signals, etc. The purpose is to eliminate the need for alignment between the optical filter and the optical filter when assembling, and to prevent displacement due to external force.

[0007]

According to a first image pickup device of the present invention, an image pickup device in which a plurality of photoelectric conversion elements are arranged, and light corresponding to one pitch of the photoelectric conversion elements are transmitted to the plurality of photoelectric conversion elements. An optical low-pass filter that diffracts the light so that the light is incident is provided, and the optical low-pass filter is integrally attached to the image sensor.

A second image pickup device of the present invention is an image pickup element in which a plurality of photoelectric conversion elements are arranged, and a refractive optical element arranged on the surface of the photoelectric conversion element at the same pitch as the pitch of the photoelectric conversion elements. And an optical low-pass filter that diffracts light corresponding to one pitch of the photoelectric conversion element so that the light is incident on a plurality of photoelectric conversion elements, and the optical low-pass filter is integrally attached to the imaging element. It is characterized by being.

A third image pickup device of the present invention is an image pickup element in which a plurality of photoelectric conversion elements are arranged, and a refraction optical element arranged on the surface of the photoelectric conversion element at the same pitch as the pitch of the photoelectric conversion elements. And an optical low-pass filter that diffracts light corresponding to one pitch of the photoelectric conversion element so as to be incident on a plurality of photoelectric conversion elements, wherein the refractive optical element is formed on one surface of the substrate, A low pass filter is formed on the other surface of the substrate, and the substrate is integrally attached to the image sensor.

Further, in each of the above image pickup devices, the optical low-pass filter can be formed by a two-dimensional diffraction grating having an uneven cross-section or a sinusoidal cross-section. Further, the optical low pass filter can be formed by a photopolymerization method.

[0011]

In the image pickup apparatus of the present invention, since the optical low-pass filter and the image pickup element are integrated, the number of parts is reduced and the number of assembling steps of the image pickup apparatus can be reduced. Also, since they are integrated in advance, it is not necessary to perform highly accurate alignment between the optical low-pass filter and the photoelectric conversion element in the assembling process of the image pickup device, and the assembling process can be facilitated and the yield rate can be improved. improves. Furthermore, if the image pickup element and the optical low-pass filter are integrated, there is no risk of displacement due to external force, and a stable image pickup apparatus can be provided.

Further, if an optical low-pass filter and a refracting optical element are provided, the optical low-pass filter can prevent the generation of false signals and the like, and at the same time, the refracting optical element focuses the light on a photoelectric conversion element to pick up an image. The sensitivity of the device can be improved.

In addition, if the refractive optical element is formed on one surface of the substrate and the optical low-pass filter is formed on the other surface of the substrate, the number of parts can be reduced, the cost can be reduced, and the imaging can be performed. The number of man-hours for assembling the device can be reduced and the assemblability can be improved.

Further, in each of the image pickup devices, when the optical low-pass filter is formed by a two-dimensional diffraction grating having a sinusoidal cross section, deterioration due to high-order light is small,
It is possible to obtain an efficient optical low-pass filter.

If the optical low-pass filter is formed by the photopolymerization method, the optical low-pass filter can be easily integrated with the image pickup device, and the photoelectric conversion device and the optical low-pass filter can be aligned with each other. Can be performed with high accuracy.

[0016]

1 is a partially cutaway sectional view showing an image pickup apparatus A according to an embodiment of the present invention. Reference numeral 1 denotes an image pickup device such as a charge-coupled device (CCD), in which photoelectric conversion elements 2 and charge transfer units 3 are two-dimensionally arranged alternately, and the photoelectric conversion elements 2 are arranged at a constant pitch p. There is. A substrate 4 made of a transparent material such as a transparent optical resin or an ultraviolet curable resin (UV resin) is integrally bonded to the surface of the image pickup device 1, and the optical low-pass filter 5 is attached to the surface of the substrate 4.
A is formed. This optical low pass filter 5A
Is formed by a two-dimensional diffraction grating having an uneven cross section (square wave shape), and has an uneven cross section in the vertical and horizontal two directions in which the photoelectric conversion elements 2 are arranged.

However, as shown in FIG. 1, the incident light 6 incident on one photoelectric conversion element 2 is diffracted in a two-dimensional direction by the optical low-pass filter 5A, and photoelectric conversion is performed immediately below. At the same time as the element 2, the light enters the surrounding photoelectric conversion element 2. As a result, a single optical low-pass filter 5A can prevent generation of false signals and the like.

Further, in this image pickup apparatus A, since the optical lowpass filter 5A and the image pickup element 1 are integrated with each other, it is not necessary to assemble the optical lowpass filter 5A and the image pickup element 1, and the optical lowpass filter is not required. The filter 5A and the image sensor 1 can be accurately aligned (especially in the optical axis direction). In addition, even if an external force such as vibration or shock is applied, the optical low-pass filter 5A
It is possible to obtain a stable image pickup apparatus A without causing a positional deviation between the image pickup element 1 and the image pickup element 1.

FIG. 2 is a partially cutaway sectional view showing an image pickup apparatus B according to another embodiment of the present invention. In this image pickup apparatus B, a lens array 8 composed of a plurality of refracting optical elements 7 having a convex lens shape and arranged at the same pitch as the photoelectric conversion elements 2 is integrally formed, and each refracting optical element 7 picks up an image. It is located above each photoelectric conversion element 2 of the element 1. Further, a substrate 4 made of a transparent material is integrally provided on the surface of the image sensor 1 from above the lens array 8, and an optical low-pass filter made of a two-dimensional diffraction grating having an uneven cross section is provided on the upper surface of the substrate 4. 5A is formed. The refractive optical element 7 and the substrate 4 have different refractive indexes.

In the image pickup device B, however, as shown in FIG. 3, the incident light 6 incident on one photoelectric conversion element 2 is diffracted in the two-dimensional direction by the optical low pass filter 5A. Received photoelectric conversion element 2 directly below
At the same time, the light enters the surrounding photoelectric conversion elements 2. further,
The incident light 6 that has passed through the optical low-pass filter 5A is subjected to a condensing action by each refractive optical element 7 and is condensed on each photoelectric conversion element 2. Therefore, in the image pickup apparatus B, the optical low-pass filter 5A can prevent generation of a false signal and the like, and the condensing action of the refractive optical element 7 can improve the sensitivity.

FIG. 4 is a partially cutaway sectional view of an image pickup device C according to still another embodiment of the present invention. This imaging device C
In this case, a two-dimensional diffraction grating having an uneven cross section is formed on the upper surface of a substrate 4 made of a transparent material, and a plurality of refractive optical elements 7 having a convex lens shape are formed on the lower surface. The substrate 4 is integrated with the image sensor 1 such that the refractive optical element 7 on the lower surface is brought into contact with the surface of the image sensor 1, and each refractive optical element 7 is positioned above each photoelectric conversion element 2. ing. In this image pickup device C, since the optical low-pass filter 5A and the refractive optical element 7 are formed on one substrate 4, the number of constituent members is reduced and the assembling property is further improved.

Further, in each of the above embodiments, the image pickup devices A, B and C using the two-dimensional diffraction grating having a concave-convex cross section as the optical low-pass filter 5A have been described, but these image pickup devices A, B and C are described. In, a two-dimensional diffraction grating having a sinusoidal cross section can be used as the optical low-pass filter.
For example, what is shown in FIG. 5 is an imaging device D that uses a two-dimensional diffraction grating having a sinusoidal cross section as the optical low-pass filter 5B in the same structure as the imaging device A of FIG. 6 shows an image pickup device E using a two-dimensional diffraction grating having a sinusoidal cross section as the optical low pass filter 5B in the same structure as the image pickup device C of FIG. The optical low-pass filter 5B has a sinusoidal cross section 2
By using the dimensional diffraction grating, it is possible to obtain an efficient optical low-pass filter 5B with less deterioration due to higher-order light as diffracted light (that is, the power of 0th-order light and first-order light is large).

7A to 7E are cross-sectional views showing a method of manufacturing the image pickup device A according to the present invention, in which the surface of the image pickup device 1 is optically formed by the so-called 2P method (photopolymerization method). This is a method of forming the low-pass filter 5A. FIG. 7A shows a stamper 9 made of a glass material that transmits ultraviolet rays (UV light), and an optical low pass filter 5A is provided on the upper surface of the stamper 9.
A profile 10A having a concavo-convex inverted shape is formed. When the imaging device A is manufactured, the ultraviolet curable resin (UV resin) 11 is added to the profile 10A of the stamper 9.
(FIG. 7B), and then the profile 10
The image sensor 1 is turned upside down on the resin 11 supplied to A (FIG. 7C), and the image sensor 1 is pressed against the surface of the stamper 9 to spread the resin 11 on the surface of the stamper 9. The resin 11 is brought into close contact with the surface of the image sensor 1 and the resin 11 is filled up to the corner of the profile 10A. Thereafter, as shown in FIG. 7D, the ultraviolet curable resin 11 is irradiated with ultraviolet rays (UV light) 12 through the stamper 9 to cure the resin 11, and the cured resin 11 cures the optical low pass filter 5A and the substrate. 4 is molded and the substrate 4 is adhered to the image pickup device 1. Next, if the resin 11 is released from the stamper 9 together with the image sensor 1,
As shown in FIG. 7E, the optical low-pass filter 5A is integrally formed on the surface of the image sensor 1.

When manufacturing the image pickup devices D and E having the optical low-pass filter 5B composed of a two-dimensional diffraction grating having a sinusoidal cross section as in the embodiment shown in FIGS. 5 and 6, FIG. As shown in FIG.
It is natural to use the stamper 9 having the two-dimensional sinusoidal profile 10B which is the inverted shape of B.

FIG. 9 shows a method for keeping the thickness of the substrate 4 constant and maintaining the distance between the optical low-pass filter 5A and the image pickup device 1 at a predetermined distance and uniformly in the above manufacturing method. It is sectional drawing shown. That is, the spacer 13 having a uniform thickness is placed on the stamper 9, and the image pickup device 1 is placed on the spacer 13 and supported by the spacer 13. Since this spacer 13 has a uniform thickness, the distance between the molded optical low-pass filter 5A and the image pickup device 1 can be maintained at a predetermined distance and uniformly, and the height of the optical low-pass filter 5A can be kept high. It becomes possible to easily perform accurate alignment.

Further, FIG. 10 is a sectional view showing another method for keeping the distance between the optical low-pass filter 5A and the image pickup device 1 uniform, and an image is picked up on the surface of the stamper 9 made of glass. A profile 10A having an area smaller than that of the element 1 and having a recess 14 with a uniform depth, and the bottom surface of the recess 14 having an inverted shape of the optical low-pass filter 5A.
Is formed. Then, with the peripheral portion of the image pickup device 1 placed on the stamper 9, the resin 11 is irradiated with ultraviolet rays 12 to be cured to form the substrate 4 having a uniform thickness, and the optical low-pass filter 5A and the image pickup device are formed. The distance from 1 can be kept uniform.

[0027]

According to the present invention, since the optical low-pass filter and the image pickup device are integrally structured, the number of parts is reduced and the number of assembling steps of the image pickup device can be reduced.
Also, since they are integrated in advance, it is not necessary to perform highly accurate alignment between the optical low-pass filter and the photoelectric conversion element in the assembling process of the image pickup device, and the assembling process can be facilitated and the yield rate can be improved. improves. Furthermore, if the image pickup element and the optical low-pass filter are integrated, there is no risk of displacement due to external force, and a stable image pickup apparatus can be provided.

Further, if an optical low-pass filter and a refracting optical element are provided, the optical low-pass filter can prevent the generation of false signals and the like, and at the same time, the refracting optical element focuses the light on a photoelectric conversion element to pick up an image. The sensitivity of the device can be improved.

In addition, if the refractive optical element is formed on one surface of the substrate and the optical low-pass filter is formed on the other surface of the substrate, the number of parts can be reduced, the cost can be reduced, and the imaging can be performed. The number of man-hours for assembling the device can be reduced and the assemblability can be improved.

Further, when the optical low-pass filter is formed by a two-dimensional diffraction grating having a sinusoidal cross section, an efficient optical low-pass filter with less deterioration due to higher-order light can be obtained, and a high-quality image pickup device is provided. can do

Further, if the optical low-pass filter is formed by the photopolymerization method, the optical low-pass filter can be easily integrated with the image pickup device, and the alignment between the photoelectric conversion device and the optical low-pass filter can be achieved. Can be performed with high accuracy, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a partially cutaway sectional view showing an image pickup apparatus according to an embodiment of the present invention.

FIG. 2 is a partially cutaway sectional view showing an image pickup apparatus according to another embodiment of the present invention.

FIG. 3 is a diagram for explaining the operation of the same.

FIG. 4 is a partially cutaway sectional view showing an image pickup apparatus according to still another embodiment of the present invention.

FIG. 5 is a partially cutaway sectional view showing an image pickup apparatus according to still another embodiment of the present invention.

FIG. 6 is a partially cutaway sectional view showing an image pickup apparatus according to still another embodiment of the present invention.

7 (a), (b), (c), (d) and (e) are cross-sectional views showing a method for manufacturing an image pickup device according to the present invention.

FIG. 8 is a cross-sectional view showing another shape of the stamper.

FIG. 9 is a cross-sectional view showing another method of manufacturing the imaging device according to the present invention.

FIG. 10 is a cross-sectional view showing another method of manufacturing the imaging device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image sensor 2 Photoelectric conversion element 4 Substrate 5A Optical low-pass filter with uneven section 5B Optical low-pass filter with sinusoidal section 7 Refractive optical element

Claims (6)

[Claims] 1. An image pickup device in which a plurality of photoelectric conversion elements are arranged, and an optical low-pass filter that diffracts light corresponding to one pitch of the photoelectric conversion elements so as to enter the plurality of photoelectric conversion elements, An image pickup apparatus, wherein the optical low-pass filter is integrally attached to the image pickup element. 2. An imaging device in which a plurality of photoelectric conversion elements are arranged, a refractive optical element arranged on the surface of the photoelectric conversion element at the same pitch as the pitch of the photoelectric conversion elements, and one pitch of the photoelectric conversion elements. An optical low-pass filter that diffracts corresponding light so as to be incident on a plurality of photoelectric conversion elements, and the optical low-pass filter is integrally attached to the image sensor. 3. An image pickup device in which a plurality of photoelectric conversion elements are arranged, a refractive optical element arranged on the surface of the photoelectric conversion element at the same pitch as the pitch of the photoelectric conversion elements, and one pitch of the photoelectric conversion elements. An optical low-pass filter that diffracts corresponding light so as to be incident on a plurality of photoelectric conversion elements, wherein the refractive optical element is formed on one surface of the substrate, and the optical low-pass filter is the other surface of the substrate. And the substrate is integrally attached to the image pickup device. 4. The image pickup device according to claim 1, wherein the optical low-pass filter is formed by a two-dimensional diffraction grating having an uneven cross section. 5. The image pickup device according to claim 1, wherein the optical low-pass filter is formed by a two-dimensional diffraction grating having a sinusoidal cross section. 6. The image pickup device according to claim 1, wherein the optical low-pass filter is formed by a photopolymerization method.