JPH11190819A - Optical system and optical module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of lenses used and to obtain a sufficient performance by using radial type refractive index lenses having high aberration compensation capabilities and satisfying specific conditions. SOLUTION: A radial type refractive index distribution lens GL1 is located on an objective body side. The material and the total body of the lens GL1 have a negative refractive index and both surfaces of the lens GL1 are made planar. The material and the total body of a radial type refractive index distribution lens GL2 have a positive refractive index and both surfaces of the lens GL2 are made planar. The lenses GL1 and GL2 are joined together to make a lens system and a diaphragm S is provided on the joint surface. Then, the system satisfies conditions |1/V1a | < 0.02 and |a/V1p | < 0.02 where V1a and V1p are the Abbe's numbers of the materials of the lenses GL1 and GL2, respectively. If these conditions are exceeded, it is difficult to compensate for the axial aberration and the color aberration of the magnification simultaneously, i.e., one of the aberrations becomes larger or both color aberrations become larger.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens and an optical system for use in an optical apparatus and an optical module using the lens and the optical system.

[0002]

2. Description of the Related Art In recent years, cameras for performing electronic imaging, such as those found in home video cameras, videophones, and door phones with cameras, have become widespread. The reduction in size, weight, and cost of lens systems used in these cameras has become a major issue. The lens system used in these cameras generally has about three to six lenses for a fixed focal length.

Further, when performing stereoscopic photography or autofocus, two optical systems, usually left and right, are required, and the number of lenses required in the optical system is twice that of a normal lens system.

[0004]

A lens system having a number of lenses of about 2 to 6 like the above-mentioned conventional lens system has a large number of lenses and a complicated lens frame structure for fixing the lenses. And cost. Further, there is a problem that the performance is deteriorated due to the eccentricity of each lens at the time of processing and assembly.

When two optical systems are required for three-dimensional photographing or the like, two lens systems are required, and it is necessary to accurately align the two lens systems.

An object of the present invention is to provide an optical system having a small number of lenses, a simple configuration, and sufficient performance.

Another object of the present invention is to provide an optical system and an optical module which are suitable for two eyes such as stereoscopic photography and autofocus.

[0008]

According to a first aspect of the present invention, there is provided:
In order from the object side, the medium and the whole are composed of a radial type gradient index lens having a negative refractive power, and the medium and the radial type gradient index lens having a whole refractive index having a positive refractive power. The following conditions (1) and ( An optical system that satisfies condition 2). (1) | 1 / V _1n | <0.02 (2) | 1 / V _1p | <0.02 where V _1n is the Abbe number of the medium of the radial refractive index distribution lens having the negative refractive power, V _1p is the Abbe number of the medium of the radial type gradient index lens having the positive refractive power.

A second configuration of the present invention has a lens system composed of a plurality of lenses and an image pickup device or a display device arranged on the image side of the lens system. Alternatively, the optical system is configured so that an air layer is not formed between the optical system and the display element. That is, in the second configuration of the present invention, the inter-lens and the final surface of the lens and the imaging element or the display element are in close contact with or joined to each other, or are filled with a resin such as an epoxy resin.

A third configuration of the present invention comprises two lens systems each including a radial type gradient index lens and an image pickup device substrate, and the two lens systems are provided on the surface of the image pickup device substrate. An optical module characterized in that a final surface is adhered and integrated.

A lens system according to a fourth aspect of the present invention comprises a single lens having a convex and flat shape, has a brightness stop inside the lens, and forms a lens close to the image-side surface (plane) of the lens. The image position is set so as to satisfy the following condition (5). (5) 0.2 <ds / f <0.8 where ds is the distance in the optical axis direction from the top of the convex surface of the lens to the aperture stop, and f is the focal length of the lens.

First, an optical system having a first configuration according to the present invention will be described.

In the present invention, a radial type gradient index lens element having a high aberration correction capability is used in order to provide an optical system with a small number of lenses and a simple structure.

In the radial type gradient index lens, the medium has a refractive index distribution in a direction perpendicular to the optical axis, and the refractive index distribution is represented by the following equation (a). _{n (r) = N 0 +} N 1 r 2 + N 2 r 4 + N 3 r 6 + ··· (a) where, N ₀ is a refractive index on the optical axis at the wavelength of the reference, N
.., ₁ , N ₂ , N ₃ ... Are coefficients representing the refractive index distribution at the reference wavelength, and r is the distance from the optical axis.

The Abbe numbers V ₀ and V _i of the radial type gradient index lens are given by the following equations (b) and (c). _{V 0 = (N 0d -1)} / (N 0F -N 0C) (b) V i = N id / (N iF -N iC) (i = 1,2, ···) (c) where N _i λ (i = 0, 1, 2,...) Is a coefficient representing the refractive index distribution at the wavelength λ, and N _id , N _iF , and N _iC are for the d-line, the F-line, and the C- line, respectively. It is a coefficient.

The partial dispersion ratio P _i (i = 0, 1, 2,...) Of the radial type gradient index lens is expressed by the following equation (d).
Given by P _i = (N _id −N _iC ) / (N _iF −N _iC ) (d)

As a lens system having a simple configuration using a radial type gradient index lens, a single radial type gradient index lens having flat surfaces on both sides as in the lens system described in JP-A-9-49966. Lens system composed of
A lens system in which a radial type gradient index lens having a negative refractive power and a radial type gradient index lens having a positive refractive power are combined as in the lens system described in JP-A-59-62816. Etc.

Of these conventional examples, Japanese Patent Application Laid-Open No. 9-4996
The lens system described in Japanese Patent Publication No. 6 requires a material having a large refractive index difference Δn between the center and the periphery in order to increase the angle of view of the lens system, and it is difficult to manufacture such a material.
Therefore, it is difficult to increase the angle of view.

The lens system described in JP-A-59-62816 combines a radial type gradient index lens having a negative refractive power and a radial type gradient index lens having a positive refractive power. Since it is a lens system for an optical pickup, it is a single-color design, and the design does not consider the off-axis performance.

Here, it is considered that a lens system is constituted by a single radial type gradient index lens having flat surfaces on both sides using a material which is easy to manufacture.

As a material which can be easily manufactured, Japanese Patent Application Laid-Open No.
It is known that a low-dispersion material having a Δn of about 0.05 can be obtained by appropriately distributing Ba ions and Ti ions as described in Japanese Patent No. 57069. As a material that can be manufactured using this manufacturing method, a material GP having the following values was assumed.

Table 1 N ₀ = 1.70000, N ₁ = -1.000 × 10 ^-2 , N ₂ = 0 V ₀ = 40.00, V ₁ (V _1p ) = 500.0 P ₀ = 0.295, P ₁ = 0.295 Effective diameter = 4 mm , Δn = 0.04

Using this material GP, a parallel plane radial type gradient index lens having the following data shown in FIG. 32 was designed. f = 6.0 mm, F / 2.8, IH = 2.0 mm, 2ω = 38.7 °, effective diameter = 4 mm r ₁ = ∞ (aperture) d ₁ = 10.4065 Material GP r ₂ = ∞ d ₂ = 2.5668 (back focus)

In the above-mentioned lens system, the stop is arranged on the first surface, whereby the Δn required for the material is reduced, and the axial chromatic aberration and the chromatic aberration of magnification can be corrected to practical levels. The principle of correcting each aberration by this lens system is as shown in Table 2 below. Table 2 is aberration correction parameter correction level spherical aberration N ₂ acceptable coma N ₂ acceptable power acceptable distortion (electrical) of the astigmatic lens thickness corrected is curvature medium uncorrected longitudinal chromatic aberration V ₁ Correction Magnification chromatic aberration V ₁ , aperture position acceptable

As shown in Table 2, coma and spherical aberration can be controlled by the parameter N ₂ , and astigmatism can be controlled by the thickness d of the lens. FIG. 31 shows the relationship between the parameter N ₂ (refractive index distribution coefficient N ₂ ) and the thickness d of the lens and the astigmatism that occurs. In FIG. 31, the curve a shows N ₂ = 2 × 10 ⁻⁵ , Curve b is N ₂
= 0, curve c is N ₂ = −2 × 10 ⁻⁵ . It should be noted that the amount of generation of distortion is practically allowable, but it can be corrected electrically if further correction is necessary.

The aberration diagram of this lens system is as shown in FIG. 33, which has sufficient performance as a lens for a video camera. However, in order to widen the angle of view, a material having a large Δn is required, and it is difficult to produce a material having a large Δn. Therefore, it is difficult to make the angle of view wider than the above value.

In order to widen the angle of view of the lens system by using a material which is easy to manufacture, a radial type gradient index lens having negative refractive power and flat on both sides is replaced with a radial type gradient index lens made of material GP. On the object side. With such a configuration, a so-called retro-focus type power arrangement is provided, and the angle of view can be widened. In this case, it is desirable that much of the power required for the lens is given to the medium instead of the surface of the gradient index lens. This is because the aberration generated in the medium can be made smaller than the aberration generated in the surface.
Therefore, it is desirable that the negative lens has a negative power to the medium, and the positive lens has a positive power to the medium.

At this time, each aberration can be corrected by using the same principle as that shown in Table 2 above. In particular, regarding the astigmatism, the thickness of the negative lens and the thickness of the positive lens may be determined so that the astigmatism of the entire system is favorably corrected according to the specifications of the lens system such as the focal length and the back focus. Therefore, it is desirable that the stop be disposed between both lenses.

The optical system according to the present invention has the above-described lens configuration for the above-described reason. However, in order to satisfactorily correct both the axial chromatic aberration and the chromatic aberration of magnification to a practically sufficient level. In addition, it is desirable to prevent chromatic aberration from occurring in the medium as much as possible. For this purpose, the conditions (1) and (2) are satisfied.

If the conditions (1) and (2) are exceeded, it becomes difficult to achieve both the correction of the axial chromatic aberration and the correction of the chromatic aberration of magnification, and either one of them becomes excessive or both chromatic aberrations become excessive. .

As described above, the optical system according to the first configuration of the present invention comprises, in order from the above-mentioned lens configuration, that is, from the object side, the medium and the entirety of the radial type gradient index lens having a negative refractive power and the medium and the entirety. An optical system composed of a radial type gradient index lens having a positive refractive power.
It satisfies (2).

In the optical system of the first configuration of the present invention described above, in order to satisfactorily correct astigmatism in the entire system, the center thickness of the radial type gradient index lens having a positive refractive power must be adjusted. It is desirable that the thickness be about 1/4 pitch, and that the following condition (3) be satisfied. (3) 0.15 <d (p) / p <0.40 where d (p) is the center thickness of the radial type gradient index lens having a positive refractive power, and p is the thickness of the radial type gradient index lens material. The pitch is given by the following equation (e). p = 2π ｛N ₀ / -2N ₁ ｝ ^1/2

When the value exceeds the upper limit or the lower limit of the above condition (3), astigmatism becomes excessive.

Considering the ease of material fabrication, it is desirable that the maximum refractive index difference Δn of the radial type gradient index lens satisfy the following condition (4). (4) When | Δn | <0.1 Δn exceeds the range of the condition (4), it becomes difficult to produce a material.

Next, an optical system having a second configuration according to the present invention will be described.

A general lens system is generally composed of about three to six lenses. In such a lens system, the performance tends to deteriorate due to the eccentricity of each lens during processing and assembly.

In order to avoid this problem, it is necessary to make the power of each lens surface as small as possible so that the effect of shifting or tilting the lens surface due to eccentricity of the lens is reduced.

The power φ on the lens surface is given by the following equation (f). φ = (n′−n) C (f) where n is the refractive index before refraction on the surface, n ′ is the refractive index after refraction on the surface, and C is the curvature of the surface.

From the above equation (f), to reduce the power of each surface, it is only necessary to reduce (n'-n) or reduce C. In order to reduce (n′−n), it is effective to form a cemented lens, that is, to prevent an air layer from being interposed between the front and rear of the lens surface. For example, in a double-colored achromatic lens, it is more resistant to eccentricity to bond both lenses to form a cemented lens than to arrange two lenses, a positive lens and a negative lens, with a space between them. Is also supported.

As a method of reducing the curvature C, it is effective to use a radial type gradient index lens and to make the surface flat by giving power to the medium.

Therefore, in the optical system of the present invention, it is effective to make the shape of the radial type gradient index lens element flat on both surfaces.

The above method of reducing (n'-n) and C
Of the two methods of decreasing the value of (1), in order to reduce (n'-n) as in the former method, a cemented lens is used, that is, an air layer is not sandwiched before and after the lens surface. A method is preferred, and this is also effective for radial type gradient index lenses. In this case, it is desirable that not only the lens be joined, but also that the lens and the image sensor be not sandwiched by an air layer. As an effective means for this, the final surface of the lens system is made flat, the optical system is configured so that the image forming position comes near this final surface, and the flat final surface is adhered to the imaging surface of the image sensor. I just need. As another method, the space between the final lens surface and the imaging surface of the imaging device may be filled with resin. In this method, the final lens surface is not limited to a flat surface but may be a curved surface.

In the above description, the image pickup system using the image pickup element has been described. However, a display element may be used as a display optical system instead of the image pickup element, and a finder or an image observation optical system can be applied.

For the above reasons, the second configuration of the present invention is as follows.
A lens system composed of a plurality of lenses and an image sensor or a display element, and a configuration in which the space between each lens and between the final lens surface and the image sensor or the display element is tightly bonded or bonded or filled with resin, and between these elements Characterized in that an air layer does not exist in the airbag.

An optical module according to a third configuration of the present invention will be described.

When two optical systems are required for stereoscopic photography, autofocus, and the like, it is necessary to accurately align the two optical systems. This alignment is troublesome and causes an increase in cost.

Here, three-dimensional photographing and phase detection autofocus will be described.

In a conventional optical system for electrically performing stereoscopic photography and phase detection autofocus, two separate lens systems are respectively mounted on different image sensors to constitute two optical systems, and these two optical systems are combined. In general, a well-aligned method is used. Therefore, alignment of two optical systems is required.

In the third configuration of the present invention, the two imaging areas are configured to be on the same plane on the same element substrate, and the final surfaces of the two lens systems are made flat, and the two lens systems are connected in the vicinity thereof. The final surfaces of the two lens systems were directly adhered to the two imaging areas so that the image positions were located. Thus, the optical axes of the two optical systems are easily made parallel to each other, so that the alignment becomes extremely easy.

Here, the element substrate is a device in which an electric circuit pattern is formed on the surface of a flat wafer made of silicon or the like, and has a function of performing imaging and receiving and emitting light.

As an optical system used in the optical module having the third configuration, an optical system having no air layer is effective. The optical system that does not include the air layer is one in which all the lenses are joined and integrated, and can be bonded to the imaging element substrate without providing a lens frame.

The fourth configuration of the present invention is the simplest configuration, which is the simplest configuration, in order to realize a lens system having an angle of view of about 50 ° and having sufficient performance for practical use. In order to make the lens easy to incorporate as an image pickup module, the surface on the image side is a plane, and an image is formed in the vicinity of this plane.

Thus, since the lens configuration is simple and one surface is flat, the lens can be manufactured at low cost. In addition, by using a single lens, it is easy to assemble, performance is less deteriorated due to eccentricity of the lens, the lens frame structure is simple, and the lens system can be manufactured at low cost.

In this lens system, it is desirable that the amount of deviation of the image plane from the surface on the lens image side in the optical axis direction satisfies the following condition (6). (6) −0.5 mm <δ <2.0 mm

By satisfying the above condition (6),
When the image sensor is used in close contact with the image-side surface of the lens,
Even if there is a defocus, the deterioration of the image can be suppressed to a small level. When the value exceeds the range of the condition (6), the deterioration of the image becomes large, which is not preferable. The reason why the upper limit of the condition (6) is larger than the lower limit is that the upper limit value on the plus side from the focus position where δ = 0 is larger in absolute value than the lower limit value on the minus side. The reason is that when the imaging surface is shifted from the image side surface of the lens to the plus side which is behind, when the image pickup surface and the lens are brought into close contact, a certain degree of defocus is corrected by the thickness of the adhesive or resin layer. Because you can do it.

In the lens system having the fourth configuration, the focal length and the image forming position are substantially determined by the radius of curvature of the first surface of the lens and the thickness of the lens. Therefore, the degree of freedom for aberration correction is limited to the position of the aperture stop.

In a wide-angle lens system having an angle of view of about 50 ° to a standard lens system, it is important to correct astigmatism, distortion, and chromatic aberration of magnification.

In the lens system having the fourth configuration according to the present invention, the position of the aperture stop is set to satisfy the above condition (5) in order to correct the aberration.
Was satisfied.

When the value exceeds the upper limit or the lower limit of the condition (5), astigmatism, distortion, and chromatic aberration of magnification are deteriorated.

Further, in the fourth configuration of the present invention, if the object-side surface of the lens is made to be an aspheric surface whose refractive power becomes weaker as going from the optical axis toward the periphery, the spherical aberration can be corrected particularly well. It is preferable because it can be performed.

In the case where the aperture stop is disposed inside the lens, the lens may be formed in a sectional shape as shown in FIG. That is, a groove-shaped constricted portion is formed in the outer diameter of the lens, and black paint 10 for light shielding is applied to the outer diameter of the lens. This has the same effect as having a stop inside the lens. If you do this,
It is possible to easily form a desired aperture with aberration correction inside the lens without increasing the number of parts.

[0062]

Next, an embodiment of the present invention will be described.

FIG. 1 is a view showing a first embodiment of an optical system according to the present invention. In the order from the object side, a radial type gradient index lens 1 having a flat surface on both surfaces, the medium and the whole having a negative refractive power.
This is a lens system in which a sheet (GL1), a medium, and a single radial refractive index distribution lens (GL2) whose both surfaces have a positive refractive power and are flat on both sides are joined, and a stop is provided on the joint surface. That is, the configuration is such that the stop S is disposed between the two refractive index distribution lenses GL1 and GL2. The data of this optical system is as follows. Example 1 f = 4.8 mm, F / 2.8, IH = 2.0 mm, 2ω = 50.1 ° r ₁ = ∞ d ₁ = 5.6713 (refractive index distribution lens GL1) r ₂ = ∞ (aperture) d ₂ = 13.5744 (refractive index Distributed lens GL2) r ₃ = ∞ d ₃ = 3.6980 (back focus) | 1 / V _1n | = 0.002, | 1 / V _1p | = 0.002 d (p) /p=0.23

The radial type gradient index lens GL1 having a negative refractive power in this embodiment is a lens material GN shown in Table 3 below, and the radial type gradient index lens GL2 having a positive refractive power is the same as that in the above table. The lens material GP shown in FIG. Table 3 N ₀ = 1.66000, N ₁ = 1.000 × 10 ^-2 , N ₂ = 0 V ₀ = 37.89, V ₁ (V _1n ) = 500.0 P ₀ = 0.295, P ₁ = 0.295 Effective diameter = 4 mm, Δn = 0 .04

The state of aberration of the optical system with respect to an object at infinity is as shown in FIG.

This optical system has an angle of view 2ω of 50.1 °, which is much wider than that of the optical system having one positive refractive power gradient index distribution lens of 38.7 °. is there. An optical system having an arbitrary angle of view between 38.7 ° and 50.1 ° can be obtained by appropriately setting the thicknesses of the two lenses.

As shown in FIG. 2, in the optical system of Example 2 which is another example of the first embodiment of the first configuration of the present invention, the medium and the whole are negative in order from the object side. One radial type gradient index lens element (GL3) having both surfaces being flat, and a radial type gradient index lens element 1 having both the medium and the entire surface having a positive refractive power and both sides being a plane.
The sheets (GL4) are spaced apart and have the following data. Example 2 f = 4.8 mm, F / 2.8, IH = 2.0 mm, 2ω = 50.0 ° r ₁ = ∞ d ₁ = 3.0000 (refractive index distribution lens GL3) r ₂ = ∞ d ₂ = 2.5249 r ₃ = ∞ (aperture) D ₃ = 12.8180 (refractive index distribution lens GL4) r ₄ = ∞ d ₄ = 2.6061 (back focus) | 1 / V _1n | = 0.002, | 1 / V _1p | = 0.002 d (p) /p=0.22

The refractive index distribution lens GL3 of Example 2 is a lens material GN shown in Table 3, and the refractive index distribution lens GL4 is a lens material GP shown in Table 1.

Still another example 3 of the optical system according to the first embodiment, which is the first configuration of the present invention, has a configuration as shown in FIG. 3, in which the medium and the whole are negative in order from the object side. One concave flattened radial refractive index distribution lens having refractive power (GL
5) and an optical system in which the medium and the entirety have a single plano-convex radial refractive index distribution lens (GL6) having a positive refractive power, and the joint surface is defined as a stop S. The data of this optical system is as follows. Example 3 f = 4.8 mm, F / 2.8, IH = 2.0 mm, 2ω = 49.0 ° r ₁ = -12.000 d ₁ = 0.8544 (refractive index distribution lens GL5) r ₂ = ∞ (aperture) d ₂ = 12.9411 (refractive Rate distribution lens GL6) r ₃ = -12.000 d ₃ = 2.6820 (back focus) | 1 / V _1n | = 0.002, | 1 / V _1p | = 0.002 d (p) /p=0.22

The materials of the gradient index lens GL5 of the third embodiment are the lens material GN and the gradient index lens GL shown in Table 3.
Material 6 is the lens material GP shown in Table 1.

FIG. 4 shows an optical system according to a fourth embodiment of the present invention.
5 is an example of an optical system having a second configuration. This example is
In the order from the object side, one radial type gradient index lens (GL) in which both the medium and the entire surface having a negative refractive power are both flat.
7), and a lens system having a configuration in which the medium and the entire surface having a positive refracting power and both surfaces have one flat radial refractive index distribution lens (GL8) are joined, and a stop S is provided on the joining surface; An image of an object at infinity is formed substantially near the final surface of the lens. That is, the radial refractive index distribution lens GL8 having a positive refractive power has a two-sided planar shape, so that the final surface of the lens system is a flat surface, and an image is formed near the flat surface of the final surface.

The fourth embodiment has the following data. Example 4 f = 4.0 mm, F / 2.8, IH = 2.0 mm, 2ω = 61.9 ° r ₁ = ∞ d ₁ = 5.5779 (refractive index distribution lens GL7) r ₂ = ∞ (aperture) d ₂ = 19.0416 (refractive index Distributed lens GL8) r ₃ = ∞ | 1 / V _1n | = 0.002, | 1 / V _1p | = 0.002 d (p) /p=0.33

The materials of the refractive index distribution lens GL7 of the fourth embodiment are the lens material GN and the refractive index distribution lens GL8 shown in Table 3.
Are the lens materials GP shown in Table 1.

The optical system having the configuration shown in FIG. 5 (the optical system of the fifth embodiment) shows an embodiment of the optical system having the second configuration of the present invention, and has a biconvex shape in order from the object side. Both the positive lens (HL1) and the biconcave negative lens (HL2), and the positive lens (HL3) having a convex flat object side surface and a flat flat image side surface are homogeneous lenses. This is an imaging lens in which three lenses are joined and integrated, and an aperture is provided on the first surface.

In the lens system of this embodiment, the best image for an object at a distance of 280 mm is formed just on the final lens (plane).

The data of the fifth embodiment is as follows. Example 5 f = 4.5 mm, F / 1.8, IH = 1.8 mm, 2ω = 47.6 ° r ₁ = 5.3757 (aperture) d ₁ = 3.7197 n ₁ = 1.81600 ν ₁ = 46.62 r ₂ = −3.9287 d ₂ = 2.8910 n ₂ = 1.59270 ν ₂ = 35.30 r ₃ = 2.4461 d ₃ = 2.7989 n ₃ = 1.81600 ν ₃ = 46.62 r ₄ = ∞

Example 6 also shows an embodiment of the lens system having the second configuration according to the present invention, and includes a lens system having a configuration as shown in FIG.

The lens system of this embodiment includes, in order from the object side, a convex-flat positive lens (HL4) having a convex surface on the object side and a flat image surface, and a plano-concave lens having a concave surface on the image surface side. Each of the negative lens (HL5) having a shape and the positive lens (HL6) having a biconvex shape is composed of three lenses which are homogeneous lenses, and these lenses are joined and integrated to form an imaging lens. It is provided on the object-side surface of the lens HL4. In the lens system of Example 6, the image side is filled with resin (SR).

In the sixth embodiment, the best image for an object having a distance of 550 mm is formed in the resin 1.0 mm behind the final surface of the lens. If the thickness of the resin SR is set to 1.0 mm, the end face of the resin SR becomes an image forming surface.

The data of the sixth embodiment is as follows. Example 6 f = 6 mm, F / 2.0, IH = 1.8 mm, 2ω = 35.0 ° r ₁ = 6.4067 (aperture) d ₁ = 4.5095 n ₁ = 1.81600 ν ₁ = 46.62 r ₂ = ∞ d ₂ = 2.7438 n ₂ = 1.53172 ν ₂ = 48.91 r ₃ = 4.2264 d ₃ = 3.9189 n ₃ = 1.88300 ν ₃ = 40.78 r ₄ = -30.4102 d ₄ = 1.0000 n ₄ = 1.49216 ν ₄ = 57.50 r ₅ = ∞ n ₄ and ν ₄ in the data Resin SR.

FIG. 7 shows an embodiment of an imaging module according to the third configuration of the present invention.

As shown in FIG. 7, two imaging areas E
In this configuration, two lens systems (a lens system LS1 and a lens system LS2) are attached to an image sensor substrate 1 having E1 and E2. The imaging device substrate is mounted on the ceramic substrate 2. The two lens systems LS1 and LS2 used in the imaging module according to the present embodiment are the lens systems according to the fourth embodiment, the final surface of which is a plane, and the vicinity of the final surface is an imaging position.

FIG. 8 shows another example of the third embodiment of the present invention, which is an optical module for performing passive autofocusing by a phase difference detection method. In this configuration, two lenses of a lens system LS1 and a lens system LS2 are attached to an imaging element substrate 1 having two imaging areas E1 and E2. The imaging element substrate 1 is mounted on a ceramic substrate 2. 7 and 8, (A) is a plan view and (B) is a side view.

The lens system L used in this embodiment
Both S1 and lens system LS2 have the following data in the configuration shown in FIG. Example 7 f = 6.248 mm, F / 2.6, IH = 1.4 mm, 2ω = 25.8 ° r ₁ = ∞ (aperture) d ₁ = 16.4658 (refractive index distribution lens GL9) r ₂ = ∞ refractive index distribution lens GL9 N ₀ = 1.6778, N ₁ = −7.6346 × 10 ⁻³ , N ₂ = 0 V ₀ = 35.19, V ₁ = 185.5 P ₀ = 0.292, P ₁ = 0.292 Effective diameter = 2.8 mm, Δn = 0.015

This lens system (the lens system of the seventh embodiment)
One radial refractive index distribution lens having a positive refractive power (GL
9), and the material is as shown in the above data.

The final surface of the lens system of this embodiment is a flat surface, and the vicinity of the image pickup surface is an image forming position. Further, the lens and the imaging area are closely adhered and joined by an epoxy-based adhesive. Actually, an adhesive layer of the order of several tens of microns exists between the final lens surface and the imaging area.

The images photographed by the lens systems LS1 and LS2 are slightly different from each other by a distance (base line length) between the two lenses, and a signal for autofocus is obtained due to this deviation. be able to.

With the configuration shown in this embodiment, the optical axes of the two lens systems are easily made parallel,
There is an advantage that no special alignment is required.
The embodiment shown in FIG. 10 is another example of the third configuration of the present invention, and is an optical module for performing infrared active type autofocus.

In FIG. 10, (A) is a plan view,
(B) is a side view. In this embodiment, as shown in (A), two lens systems of a lens system LS3 and a lens system LS4 are attached to an element substrate having a light emitting unit 3 and a light receiving unit 4. The lens system used in this embodiment is a lens system having the same data as the lens system shown in FIG. 9, and its final surface is a plane, and is configured to form an image near this final surface. Also in this embodiment, the lens and the imaging area are closely adhered with an epoxy-based adhesive, and in practice, an adhesive layer of several tens of microns is formed.

In this embodiment, the infrared light emitted from the light emitting section is condensed by the lens system LS3 and projected on the target object, and the infrared light reflected and scattered by the target object passes through the lens LS4. And returns to the light receiving section to detect the position of the spot of the light returned to the light receiving section, and measures the object distance based on the detected position.

This embodiment also has two lens systems LS
The optical axes of the LS4 and LS4 are easily parallelized, and no special alignment is required.

In the above Examples 4, 5, 6, 7 (FIGS.
The lens system shown in (6) and (7) can be used as a normal imaging optical system by placing an imaging device such as a CCD at the image forming position. By placing a display element such as an LCD at the image forming position of these lens systems, it can be used as a display optical system.

FIG. 11 shows an example in which the lens system is used as a display optical system.
S is configured so as to be in close contact with no air layer. The light from the display element 5 is made substantially parallel by the lens system LS, and if the eye 6 is observed close to the lens system, an enlarged image of the display pattern can be observed. 7 is a backlight.

FIG. 13 shows a fourth configuration of the fourth embodiment of the present invention.
The optical system according to the embodiment is a lens system according to Example 8 of the present invention.

Example 8 has a configuration as shown in FIG. 13 and comprises a convex flat lens HL10 having a convex surface facing the object side, and the lens-side surface of the lens is spherical. The stop S is arranged inside the lens HL10, and is set so that the paraxial image point for an object at infinity is located on the image-side surface of the plano-convex lens HL10.

The data of the eighth embodiment is as follows. Example 8 f = 4.0 mm, F / 2.8, IH = 2.0 mm, 2ω = 53.8 ° r ₁ = 1.9696 d ₁ = 1.4656 n ₁ = 1.42941 ν ₁ = 57.66 r ₂ = ∞ (aperture) _{d 2 = 4.5040 n 2 = 1.49241} ν 2 = 57.66 r 3 = ∞ ds / f = 0.37

FIG. 14 shows a ninth embodiment of the optical system according to the present invention, which is an optical system having a fourth configuration according to the present invention.

As shown in FIG. 14, the ninth embodiment includes a convex flat lens HL11 having a convex surface facing the object side, and the surface on the object side is a spherical surface. The stop S is disposed inside the lens. Also in this embodiment, the paraxial image point for an object at infinity is formed on the image-side surface of the lens HL11. Example 9 f = 4.0 mm, F / 2.8, IH = 2.0 mm, 2ω = 54.4 ° r ₁ = 3.0900 d ₁ = 2.0904 n ₁ = 1.77250 v ₁ = 49.60 r ₂ = ∞ (aperture) d ₂ = 4.9996 n ₂ = 1.777250 v ₂ = 49.60 r ₃ = ∞ ds / f = 0.523

FIG. 15 shows a tenth embodiment of the optical system according to the present invention, which is an optical system having a fourth configuration.

The tenth embodiment, as shown in FIG.
A convex plano lens HL having a convex surface facing the object side in order from the object side
12 and a flat glass P. The stop S of this lens system is disposed inside the convex flat lens HL12, and the object-side surface of the lens HL12 is spherical. The paraxial image point for an object at infinity is formed on the image-side surface of the flat glass.

The data of the tenth embodiment is as follows. Example 10 f = 4.0 mm, F / 2.8, IH = 2.0 mm, 2ω = 53.9 ° r ₁ = 1.9696 d ₁ = 1.4227 n ₁ = 1.49241 ν ₁ = 57.66 r ₂ = ∞ (aperture) _{d 2 = 2.5785 n 2 = 1.49241} ν 2 = 57.66 r 3 = ∞ d 3 = 2.0000 n 3 = 1.51633 ν 3 = 64.14 r 4 = ∞ ds / f = 0.36

FIG. 16 shows an eleventh embodiment of the optical system according to the present invention, which is an optical system having a fourth configuration.

In the eleventh embodiment, as shown in FIG. 16, a convex flat lens HL12 having a convex surface facing the object side in order from the object side.
And the flat glass P, and the surface on the object side is a spherical surface. The stop S is disposed between the convex flat lens HL12 and the flat glass P. The paraxial image point for an object at infinity is located on the image-side surface of the flat glass P.

The data of the eleventh embodiment is as follows. Example 11 f = 4.0 mm, F / 2.8, IH = 2.0 mm, 2ω = 52.8 ° r ₁ = 2.4186 d ₁ = 2.2701 n ₁ = 1.62041 ν ₁ = 60.29 r ₂ = ∞ (aperture) d ₂ = 4.0000 n ₂ = 1.51633 ν ₂ = 64.14 r ₃ = ∞ ds / f = 0.57

The optical systems of the eighth and ninth embodiments are composed of only a single lens, and have a configuration in which the image side surface of the lens is a plane and an image is formed near this plane. Since this optical system has a flat image side surface, it is a very convenient configuration for forming an imaging module integrated with an imaging device such as a CCD.

FIG. 17 shows a fourth embodiment of the lens system according to the present invention, which is an image pickup module in which the lens system of the eighth embodiment shown in FIG. 13 and the image pickup device are integrated. In FIG. 17, 31 is a lens system, 12 is an imaging chip of the imaging device, 13 is an imaging surface of the imaging device, 34 is a ceramic substrate of the imaging device,
The plane portion which is the final surface of the lens system 31 (the lens HL10 of Example 8) is directly bonded to the imaging chip of the imaging device. An epoxy adhesive or the like is used for bonding the imaging chip 32 to the lens HL10.

In this module, if an image of an object at a predetermined distance is formed on the imaging surface, this image can be captured.

At this time, it is possible to image an object in a fairly wide range around a predetermined distance depending on the depth of field.

FIG. 18 shows a device in which the lens system having the fourth configuration and the image pickup device are integrated. The device in which the lens and the image pickup device are integrated with resin is used. And the imaging surface are brought into optical close contact with each other.

In this figure, 35 is a lens system, 36 is an imaging chip of an imaging device, 37 is an imaging surface of the imaging device, 38
Denotes a ceramic substrate of the imaging element, and a space between the lens system 35 and the imaging chip 36 is filled with a resin 39.

In this device, if the configuration of the lens system and the thickness of the resin 39 are adjusted so that an image of the object is formed on the imaging surface 37, an object image at a predetermined distance can be taken. In this case, it is possible to image an object in a fairly wide range around a predetermined distance depending on the depth of field.

In general, the lens system itself, the lens holding member, and the imaging surface of the image sensor may vary the imaging surface of the lens from the imaging surface after assembly due to variations in the imaging surface. Therefore, after the imaging system is assembled, the lens must be moved and adjusted so that the image plane of the lens system is on the imaging surface.

With the configuration as shown in FIG. 18, variations in the lens system itself, the lens holding member, the image pickup surface of the image pickup device, and the like can be extremely reduced, and the image forming surface of the lens system can be adjusted without adjustment after assembly. And the imaging surface of the imaging element can be easily matched.

In the conventional imaging system, a low-pass filter and an infrared cut filter are arranged behind the lens system.

In the imaging device of the present invention shown in FIGS. 17 and 18, the lens system and the imaging device are integrated, so that a low-pass filter or an infrared cut filter cannot be arranged. However, this can be coped with by providing the lens constituting the lens system with the following infrared cut filter function or low pass filter function.

In order to provide an infrared cut filter function, an infrared light absorbing element such as copper ion is included in the glass material constituting the lens, or the infrared light is applied to the object side surface of the lens. For example, a coating for cutting may be applied.

Further, in order to provide a low-pass filter function, a method of increasing the point image intensity distribution to a pixel pitch at which moiré is generated due to blurring or diffraction blurring due to aberration of the lens system, A method of forming a diffraction pattern for eliminating moiré on a surface may be considered.

Next, a description will be given of a configuration of an image pickup device IC chip which is optimal when configuring the above-described image pickup module.

Normally, a bonding electrode for taking out an electric signal is arranged around the imaging surface of the imaging element, and this electrode is used by connecting with a wire or the like. However, the above-described imaging module cuts an optically unnecessary part (shown by C in the figure) on the final surface of the lens system 11 as shown in FIG. 19 to secure a space for connection. It is necessary to prevent interference between the lens and the connection part. In this case, it is necessary to process the lens into a complicated shape, which increases the cost.

In FIG. 19, 31 is a lens, 32 is an imaging chip, 33 is an imaging surface, and 34 is a ceramic substrate. 46 is a bonding electrode and 47 is a connection.

In the present invention, in order to solve the above-mentioned drawback,
The configuration was as shown in FIG. In the figure, 41 is a lens, 42 is an image sensor substrate (IC chip), 43 is an effective photoelectric conversion surface, 44 is an invalid photoelectric conversion pixel and a circuit group,
5 is a flexible electric board, 46 is a bonding electrode, and 57 is a connection.

As shown in FIG. 20 (B), the bonding electrode 46 is arranged away from the contact surface between the lens 41 and the image pickup device substrate 42, and even when the lens 41 is in close contact with the lens 41, 42 does not interfere. To achieve such a configuration, the two-dimensional image sensor has a flat surface that covers the effective photoelectric conversion surface 43 of the image sensor substrate 42 and that can be bonded to a portion of the image sensor substrate 42 other than the bonding area. Is desirable.

Reference numeral 48 denotes a light-shielding paint for cutting harmful light from the side surface of the lens, and it is desirable to cover the lens side surface and the adhesive surface with the light-shielding paint.

FIG. 21 shows a case where only a single lens is used as in the eighth and ninth embodiments, and a stop is arranged in the lens.
FIG. 4 is a diagram illustrating an example of a means for forming a stop. As shown in this figure, a constriction of a groove may be formed in the lens L, and the portion indicated by S may be used as an aperture. Also in the case of this lens, it is desirable to provide a light-shielding paint 10 for cutting out harmful light.

Instead of the single lens described above, FIGS.
As a configuration in which a convex-flat homogeneous medium single lens having a shape as shown in (1) and a flat glass are joined, the lens configuration can be optically similar to the above-described single lens. That is, as shown in FIGS. 22 and 23, in order from the object side, a convex-planar lens 51 or 54, and an aperture 53 or 56 provided inside or on the image plane of the lens, and in the plane of the convex-planar lens. A desired lens system can be formed by adhering the flat glass 52 or 55 so that the image forming position is located near the plane of the flat glass on the lens side.

In this case, it is desirable that the deviation δ ′ of the image plane in the optical axis direction from the image-side plane of the flat glass (surface opposite to the lens-side surface) satisfies the following condition (7). (7) −0.5 mm <δ ′ <20 mm

When this condition (7) is satisfied, when the imaging element is used in close contact with the image-side surface of the flat glass, image deterioration due to defocus can be suppressed to a small level. The upper limit of this condition (7) -0.5 mm or the lower limit of 20 mm
In any case, the deterioration of the image becomes large. Further, the reason why the upper limit range is larger than the lower limit range is that, as in the case of the condition (6), the image forming surface is shifted backward from the image-side surface of the flat glass (to the opposite side from the lens side). This is because a certain degree of out-of-focus can be corrected by the thickness of the adhesive layer or the resin layer used when closely contacting the imaging surface.

It is desirable that the position of the aperture stop be located inside the lens or on the image side and satisfy the following condition (5-1). _{(5-1) 0.2 <d s /} f s <0.8

As in the case of the single lens shown in FIG. 21, it is conceivable that the aperture stop is formed by forming a groove-shaped constriction on the convex / planar lens.

As another method, as shown in FIG. 22, a stop can be formed by interposing a ring-shaped light shielding member 53 between a convex flat lens 51 and a flat glass 52 so as to be integrated.

Further, as shown in FIG. 23, the convex / planar lens 54 is processed into a step shape, and a ring-shaped light shielding member 56 is adhered thereto to form a stop.

Next, a description will be given of an image pickup module having a downsized structure including an image pickup device and its holding structure in order to make the entire image pickup module small.

FIG. 24 shows an example in which an image pickup surface 63 of an image pickup element 62 is brought into close contact with a flat surface on the image side of a flat glass substrate 61 so that an image is formed on the most image side surface. It is. By doing so, it is possible to use the flat glass substrate 61 as a holding substrate for the entire imaging module.

FIG. 25 shows an example in which a flat glass substrate as shown in FIG. 24 is used as a holding substrate for the entire image pickup module. In the figure, 65 is a substrate holding member, and 66 is a camera.

The imaging module having the structure shown in FIGS. 24 and 25 has a convex lens 60 as an optical element on a substrate 61.
By arranging the imaging element 62 and the imaging element 62, the optical element and the imaging element can be integrated,
Assembly becomes easy.

If the image pickup system is configured by using these image pickup modules together with other optical elements, the size of the entire apparatus can be reduced. Further, by making the substrate transparent like the flat glass substrate 61, the substrate can have various optical functions as described later. Further, by configuring the substrate as a part of the module, it is possible to reduce the number of components and to reduce the size.

As described above, the electronic image pickup optical system usually requires that an infrared cut filter and a low-pass filter be arranged in the optical system. An imaging module as shown in FIG. 23 of the present invention can have this filter function. In order to have an infrared cut filter function,
The convex-planar lens or the flat glass may contain metal ions such as copper for cutting infrared light.

As another method for providing an infrared light cut filter function, there is a method of applying an infrared light cut coat to the object side surface of the convex / planar lens.

In order to provide the image pickup module of the present invention with a function of a low-pass filter, a quartz low-pass filter may be used instead of the flat glass, or an aberration may be generated in the lens system, or the point image intensity distribution may be caused by diffraction blur. And a method of forming a diffraction pattern on the object-side surface of the lens to eliminate moire.

Next, another imaging module according to the present invention will be described. When two optical systems are required for three-dimensional imaging, autofocusing, and the like, it is necessary to accurately align the two optical systems, and this alignment takes time and effort, leading to an increase in cost.

Here, an imaging module that performs stereoscopic photography and phase detection autofocus will be described as an imaging module requiring two optical systems.

A conventional optical system for electrically performing stereoscopic imaging and phase detection autofocusing is a method in which two separate lens systems are attached to separate image sensors, and these two lens systems are used in alignment. Is common. Therefore, alignment of two optical systems is required.

In the present invention, as shown in FIG. 26, the two imaging areas 73 and 74 are made to be on the same plane on the same element substrate 72, and the final surfaces of the two lens systems 70 and 71 are made flat. After the image forming position is located near this plane, the imaging surfaces of the two lens systems are directly attached to the two imaging areas. In this way, the optical axes of the two optical systems can be easily parallelized and alignment can be easily performed.

Here, the element substrate 72 is formed by forming an electric circuit pattern on the surface of a flat wafer made of silicon or the like.
It has a function of imaging, generating and receiving light. The lens system used here is the above-mentioned lens system of the present invention, which is a convex-planar lens, or a lens system combining a convex-planar lens and a flat glass. Since these lens systems are integrated, they can be in close contact with the imaging element substrate without using a lens frame.

The lens system according to the present invention is, for example, a lens system described in Embodiments 8, 9, 10, and 11, and if an image pickup device such as a CCD is arranged at the image pickup position of the lens system, ordinary image pickup is possible. It can be used as an optical system, and if a display element such as an LCD is arranged at an image forming position of a lens system, it can be used as a display optical system.

FIG. 27 shows a configuration when the lens system of the present invention is used as a display element.

As shown in FIG. 27, the display element 80 and the lens system 81 are brought into close contact with each other, and the light from the display element 80 is converted into a parallel light beam by the lens system 81. When the eye 82 is brought closer to the lens system 81, the pattern on the display element can be observed in an enlarged manner. 83 is a backlight.

Next, a distance measuring optical system based on the active triangulation method using the module of the present invention will be described.

FIG. 28 is a layout diagram of a distance measuring optical system based on the active triangulation method, 11 is an infrared light emitting diode (IRED) as a light emitting section for intermittently projecting infrared light, and 12
Is a light projecting lens that guides the infrared light emitted by the infrared light emitting diode 11 to the object O, 13 is a light receiving lens that collects infrared light reflected by the object O, and 14 is a light collecting lens that is collected by the light receiving lens 13. A semiconductor light position detection element (PSD) as a light receiving unit that receives infrared light and outputs two types of currents (electric signals I ₁ and I ₂ ) corresponding to the light receiving position. Here, the light projecting lens 12 and the light receiving lens 13 are each shown by a single biconvex lens, but are actually those shown in FIG.

In the distance measuring optical system having such a configuration, when the infrared light emitting diode 11 emits light, a part of the light emitted from the infrared light emitting diode is projected on the subject O through the light projecting lens 12, and Part of the light projected on the subject O is reflected by the subject O and is imaged on the surface of the light position detecting element 14 by the light receiving lens 13.

Here, in FIG.
X is the imaging position on the surface of the lens, and the projection lens 12 and the light receiving lens 1
Assuming that the principal point interval distance (base line length) of No. 3 is L, the focal length of the light receiving lens 13 is f ₁₃ , and the distance to the subject is 1, the following equation is established. x = L · f ₁₃ / l (g)

As shown in FIG. 28, the starting point of the image forming position x passes through the principal point of the light receiving lens 13 and is parallel to the straight line connecting the emission center of the infrared diode 11 and the principal point of the light projecting lens 12. This is the intersection between the straight line and the light position detecting element 14.

The infrared light emitting diode 11 of the two types of currents I ₁ and I ₂ output from the light position detecting element 14
The signals I ₁ and I ₂ excluding the current components due to the infrared light that have been projected by the object O and have been reflected by the subject O and reached the light position detecting element 14, that is, the current components due to the sunlight and the illumination light have been described above. It can be expressed by the following equation as a function of the imaging position x. I ₁ = {(a + x) / tp} · Ipφ (h) I ₂ = {tp− (a + x) / tp} · Ipφ (i) where Ipφ is the total signal light current and tp is the total length of the optical position detecting element 14. , A are the starting point of the imaging position x and the light position detecting element 1
4 is the distance between the infrared light emitting diode 11 and the end on the side of the infrared light emitting diode 11.

From the above equations (g), (h) and (i), the following equation (k) is established. 1 / l = [tp · {I ₁ / (I ₁ + I ₂ )} − a] / (l · f ₁₃ ) (k)

Signal I output from light position detecting element 14
₁ and I ₂ are sent to the judgment circuit 15 shown in FIG. ₂ and the distance to the subject O is calculated from the signal currents I ₁ and I ₂ using the above equation (k) to obtain a distance measurement signal I.

Expression (k) indicates that the infrared light emitting diode 1
This also holds when the position where 1 is disposed is not on the optical axis of the light projecting lens 2.

FIGS. 29 and 30 show an example in which the optical module of the present invention is applied to a split focus detecting device using light transmitted through a photographic lens of a camera.

Referring to FIG. 29, reference numeral 21 denotes a photographing lens;
Is a condenser lens for forming an image of the exit pupil of the taking lens 21, and these lenses 21 and 22 are arranged so that their optical axes coincide. Reference numerals 23 and 24 denote relay lenses disposed at or near the position where the image of the exit pupil of the photographing lens 21 is formed by the condenser lens 22. Reference numerals 25 and 26 denote photoelectric conversion means.
Reference numeral 24 denotes a position where a subject image is formed. By comparing the signals from the photoelectric conversion units 25 and 26, the in-focus state of the photographing lens 21 with respect to the subject can be detected.

As shown in FIG. 29, this focusing device has relay lenses 23, 24 and photoelectric conversion means 25, 26 integrated with each other.

FIG. 30 is a diagram showing the detecting means of the focus detecting device shown in FIG. 29. The principle of the focus detecting operation will be described with reference to FIG.

When the photographing lens 21 is in focus with respect to the object O, the image 30 of the object indicated by the arrow group 30
Assume that the state is A. In this state, when the photographing lens 21 is extended forward with respect to the subject O (when moved in a direction approaching the subject O), the image on the light receiving surface is 30B.
State. Conversely, when the taking lens 21 is retracted (moves in a direction away from the subject O), the image on the light receiving surface is in a state of 30C. Therefore, a plurality of minute photoelectric conversion elements are used as the photoelectric conversion means 25 and 26 in FIG.
, The image sensors 25 and 26 arranged as Y ₁ to Y ₆ and Z _{1 to} Z ₆ are used by the scanning circuit 9 to connect the photoelectric elements of the image sensors 25 and 26 to Y _{1 to} Y ₆ Z, respectively. synchronously scanning at the same timing in the direction of ₁ to Z _6, each photoelectric element to output a phase signal corresponding to the brightness of the image to be received. At the time of out-of-focus, the phase comparison circuit 27 detects a leading or lagging phase between the two phase signals, so that the phase is shifted to either the focused state or the out-of-focus state. Can be detected by the meter 28, for example.

Next, an observation module using the lens system of the present invention will be described.

FIG. 34 is a diagram showing an example of an observation module using the lens system of the present invention. A plano-convex lens 90 as an optical element and an LCD (92) as a display element are provided on a glass substrate 91 of a plane parallel plate. Are arranged.

A plano-convex lens 9 is provided on one surface of the glass substrate 91.
The LCD (92) is disposed so as to be in contact with the surface of the glass substrate 91 and the other surface of the glass substrate 91, and the glass substrate 91 is supported by the outer frame 93. The outer frame 93 is provided with a cover glass 94. LC
The optical axis 95 from D (92) to the eye 96 is straight.

In this observation module, the light beam from the LCD (92) reaches the observer's eye 96 via the glass substrate 91, the plano-convex lens 90 and the cover glass 94, and the LCD (9)
The display of 2) can be observed.

The observation module shown in FIG. 34 has a plano-convex lens 90 as an optical element and a display element 9 on a substrate 91.
2, the optical element 90 and the display element 9 are arranged.
2 can be integrally formed, so that assembly is facilitated.

Further, for example, if this observation module is used together with other optical elements to form an observation system, the size of the entire apparatus can be reduced. In addition, if the substrate is a transparent substrate such as a flat glass substrate, the substrate can have various optical functions. Furthermore, if the substrate is configured as a part of the module, the number of components can be reduced and the module can be reduced in size.

The reference wavelength of the data in each embodiment is the d line.

In the present invention, in addition to the constitution described in the claims, the optical system or the optical module described in the following items can also achieve the object of the invention.

(1) The optical system according to claim 1, wherein a stop is provided between a radial type gradient index lens having a negative refractive power and a radial type gradient index lens having a positive refractive power. An optical system characterized by disposing.

(2) The optical system according to claim 1 or (1), wherein the following condition (3) is satisfied.
An optical system characterized by satisfying. (3) 0.15 <d (p) / p <0.40

(3) The optical system according to claim 1 or (1) or (2), characterized by satisfying the following condition (4). (4) | Δn | <0.1

(4) The optical system according to claim 1 or (1), (2) or (3), wherein the radial type gradient index lens having a negative refractive power is provided. An optical system characterized by being joined with a radial type gradient index lens having a positive refractive power.

(5) The optical system according to claim 1 or (1), (2), (3) or (4), wherein the radial refraction has a negative refractive power. An optical system characterized in that both the gradient index lens and the radial type gradient index lens having a positive refractive power are both flat surfaces.

(6) The optical system according to claim 2, wherein the optical system includes a radial type gradient index lens.

(7) The optical system according to claim 2, comprising three homogeneous lenses.

(8) The optical module according to claim 3, wherein an air layer is not interposed between the most object-side lens surface of the two lens systems and the imaging surface. module.

(9) In the optical module according to the third aspect of the present invention, the element substrate is an image sensor substrate having two image pickup areas, and the last of the two lens systems is provided in the two image pickup areas. An optical module characterized in that the surfaces are closely contacted and integrated, and stereoscopic imaging is performed by the two imaging areas.

(10) The optical module according to claim 3, wherein the element substrate is an imaging element substrate having two imaging areas, and the final surfaces of the two imaging areas are in close contact with each other. An optical module which is integrated so as to obtain a phase signal for auto-focusing based on signals from the two imaging areas.

(11) In the optical module according to the third aspect of the present invention, the element substrate has a light emitting portion and a light receiving portion, and the light emitting portion and the light receiving portion each have the last of the two lens systems. An optical module characterized in that the surfaces are integrated in close contact with each other, and a signal for auto-focusing is obtained by an electric signal from the light receiving unit using the principle of triangulation.

(12) Consisting of a convex-flat homogeneous lens and a brightness stop arranged inside the lens, the imaging position is arranged near the plane side of the lens, and the following condition (5) An optical system characterized by satisfying the following. (5) 0.2 <ds / f <0.8

(13) An image pickup module characterized in that the image pickup surface of the image pickup element or the display surface of the display element is closely attached to the lens flat portion of the optical system described in the above item (12).

(14) Consisting of a convex and flat homogeneous lens, a brightness stop arranged inside the lens, and a flat glass closely attached to the plane of the lens, the flat glass is located near the image side plane of the flat glass. An optical system which is configured so that an image forming position is located and satisfies the following condition (5). (5) 0.2 <ds / f <0.8

(15) The optical element described in the above (14) is characterized in that an image pickup device having an image pickup surface closely attached or a display device having a display surface adhered closely is provided on the image side flat portion of the flat glass of the optical system. Imaging module.

(16) A two-dimensional image pickup device substrate which fully covers the effective photoelectric conversion surface on the image pickup device substrate and has a flat surface to which a portion other than the bonding area on the image pickup device substrate can be adhered.

(17) 2 described in the above item (16)
A two-dimensional image sensor substrate and an optical system (lens system) having a substantially flat surface on the image side, wherein the substantially flat surface of the optical system is optically disposed in close contact with the surface of the image sensor substrate; An imaging module, wherein a bonding electrode on a two-dimensional imaging element substrate is outside a surface in close contact with the optical system.

(18) The imaging module according to the above (17), wherein a light-shielding paint is provided on a surface other than the object-side incident surface of the optical system.

(19) Two optical systems and one element substrate are provided, and the two optical systems are integrated on the surface of the element substrate such that their final surfaces are in close contact with each other. Imaging module.

(20) An imaging module in which an optical element and an imaging element are arranged on a substrate.

(21) An imaging module in which an optical element and an imaging element are arranged on a transparent substrate.

(22) The imaging module according to the above (21), wherein a light beam enters the imaging device via at least the optical element and the transparent substrate.

(23) In the module described in the above item (21), the optical element is arranged so as to be in contact with one surface of the transparent substrate, and the imaging element is arranged so as to be in contact with the surface on the opposite side. An imaging module characterized by the above-mentioned.

(24) The imaging module according to (21), (22) or (23), wherein no space exists between the transparent substrate and the optical element. .

(25)) The above (21), (22),
An imaging module according to (23) or (24), wherein the light beam is transmitted without being reflected in the transparent substrate.

(26) The imaging module according to the above (23), wherein the optical element is located in front of the imaging surface of the imaging element.

(27) The above (21), (22), (2)
3) The module described in (24), (25) or (26), wherein the transparent substrate is a parallel plane plate.

(28) The above (21), (22), (2)
An imaging module according to the item (3), (24), (25), (26) or (27), wherein the principal ray is a straight line.

(29) The above (20), (21), (2)
2), (23), (24), (25), (26), (2)
(7) The imaging module according to (28), wherein the substrate in the module is supported by another holding member.

(30) The above (20), (21), (2)
2), (23), (24), (25), (26), (2)
(7) The imaging module according to (28), wherein only the substrate in the module is supported by another holding member.

(31) An observation module in which an optical element and a display element are arranged on a substrate.

(32) An observation module in which an optical element and a display element are arranged on a transparent substrate.

(33) The observation module according to the above (32), wherein a light beam from the display element is observed through at least a transparent substrate.

(34) In the module described in the above item (32), the optical element is arranged so as to be in contact with one surface of the transparent substrate, and the display element is in contact with the other surface of the transparent substrate opposite to this. Observation module characterized by being arranged as follows.

(35) An observation module according to the above (32), (33) or (34), wherein there is no space between the transparent substrate and the optical element. .

(36) The above (32), (33), (3)
(4) The observation module according to (35), wherein the light beam is transmitted without being reflected in the transparent substrate.

(37) The observation module according to the above (34), wherein the optical element is located in front of the display surface of the display element.

(38) The above (32), (33), (3)
4) The module described in (35), (36) or (37), wherein the transparent substrate is a parallel plane plate.

(39) The above (31), (32), (3)
(3) An observation module according to (34), (35), (36), (37) or (38), wherein the principal ray is a straight line.

(40) The above (31), (32), (3)
3), (34), (35), (36), (37), (3
8) The observation module according to the item 8 or 39, wherein the substrate in the module is supported by another holding member.

(41) The above (31), (32), (3)
3), (34), (35), (36), (37), (3
8) The observation module according to the item 8 or 39, wherein only the substrate in the module is supported by another holding member.

[0211]

According to the present invention, it is possible to obtain an optical system for optical equipment which has a low cost and a high performance with a small number of lenses. In addition, the present invention can realize an optical module that performs stereoscopic photography, autofocus, and the like with extremely easy alignment.

[Brief description of the drawings]

FIG. 1 is a sectional view of an optical system according to a first embodiment of the present invention.

FIG. 2 is a sectional view of Embodiment 2 of the optical system of the present invention.

FIG. 3 is a sectional view of a third embodiment of the optical system according to the present invention;

FIG. 4 is a sectional view of an optical system according to a fourth embodiment of the present invention.

FIG. 5 is a sectional view of an optical system according to a fifth embodiment of the present invention.

FIG. 6 is a sectional view of an optical system according to a sixth embodiment of the present invention.

FIG. 7 is a diagram showing an example of the configuration of an optical module according to the present invention.

FIG. 8 is a diagram showing another example of the configuration of the optical module of the present invention.

FIG. 9 is a sectional view of an optical system according to a seventh embodiment of the present invention.

FIG. 10 is a diagram showing another example of the configuration of the optical module of the present invention.

FIG. 11 is a diagram showing a configuration when the optical system of the present invention is used as a display optical system.

FIG. 12 is an aberration curve diagram according to the first embodiment of the present invention.

FIG. 13 is a sectional view of an optical system according to an eighth embodiment of the present invention.

FIG. 14 is a sectional view of an optical system according to a ninth embodiment of the present invention.

FIG. 15 is a sectional view of an optical system according to a tenth embodiment of the present invention.

FIG. 16 is a sectional view of Embodiment 11 of the optical system of the present invention.

FIG. 17 is a diagram illustrating a configuration of an imaging module using an optical system including a single lens according to the invention.

FIG. 18 is a diagram showing another configuration of an imaging module using an optical system including a single lens according to the present invention.

FIG. 19 is a diagram showing a configuration of a conventional imaging element substrate.

FIG. 20 is a diagram showing a configuration of an image sensor substrate of the present invention.

FIG. 21 is a diagram showing a means for forming an aperture in a single lens.

FIG. 22 is a diagram showing a configuration in which the single lens of the present invention and a flat glass are joined.

FIG. 23 is a diagram showing another example of a configuration in which the single lens of the present invention and a flat glass are joined.

FIG. 24 is a diagram showing a configuration of an image pickup module using an optical system in which a single lens and a flat glass are joined according to the present invention.

FIG. 25 is a diagram showing another example of an imaging module using an optical system in which a single lens and a flat glass are joined according to the present invention.

FIG. 26 is a diagram showing a configuration of an imaging module using two optical systems according to the present invention.

FIG. 27 is a diagram showing a configuration of a display device using the optical system of the present invention.

FIG. 28 is a layout diagram of a distance measuring optical system based on an active triangulation method.

FIG. 29 is a diagram showing a configuration of a focus detection device using the optical system of the present invention.

FIG. 30 is a diagram showing detection means by the focus detection device.

FIG. 31 is a diagram showing the relationship between the thickness of a radial type gradient index lens and astigmatism;

FIG. 32 is a cross-sectional view of a conventional radial type gradient index lens.

FIG. 33 is an aberration curve diagram of the lens shown in FIG. 14;

FIG. 34 is a diagram showing a configuration of an observation module using the optical system of the present invention.

Claims (3)

[Claims] 1. A radial refractive index distribution lens having a medium and the whole having a negative refractive power, and a radial refractive index distribution lens having a medium and the whole having a positive refractive power. An optical system that satisfies (1) and (2). (1) | 1 / V _1n | <0.02 (2) | 1 / V _1p | <0.02 where V _1n is the Abbe number of the medium of the radial type gradient index lens having the negative refractive power, V _1p is the Abbe number of the medium of the radial type gradient index lens having the positive refractive power. 2. A lens system comprising a plurality of lenses and one imaging element or display element, wherein the lens system is in close contact with each other so that no air layer exists between each lens and between the lens and the imaging element or display element. An optical system characterized by being bonded or filled with resin. 3. A lens system comprising two lens systems each having a radial type gradient index lens element and one element substrate, wherein the final surfaces of the two lens systems are respectively brought into close contact with the surface of the element substrate to be integrated. An optical module, comprising: