JP2010151861A - Camera module, camera, and cellular phone with camera - Google Patents

Abstract

A camera module having a small number of lenses and capable of being further reduced in size, a camera using the camera module, and a mobile phone with a camera are provided.
A camera module 1 according to the present invention includes a prism 3 that reflects light incident from the object side at a predetermined angle and emits the light to an image side, and lens groups 5, 7, and 9 provided on the image side of the prism 3. And an imaging body 13 that forms an image on a surface provided on the image side of the lens groups 5, 7, and 9, and the prism 3 forms at least one of the object side surface (1) and the image side surface (2) as a curved surface. Lens function.
[Selection] Figure 1

Description

  The present invention relates to an optical camera module used for a small camera, a camera equipped with the camera module, and a camera-equipped mobile phone.

  In recent years, with the thinning of mobile phones, there is a demand for thinning of cameras mounted on mobile phones. On the other hand, Patent Document 1 discloses that in a camera module mounted on a mobile phone, the optical axis of a lens group is shifted by 90 degrees from incident light of an object (subject) by a prism. Yes.

  In the camera module of Patent Document 1, an objective lens (a meniscus lens having a negative refractive power with a convex surface facing the object side) is provided on the light incident side (object side) of the prism, and the light exit side of the prism On the (image side), a light focusing lens having a positive refractive power with a convex surface facing the image side is disposed.

JP 2006-58363 A

  However, in the technique of Patent Document 1, an objective lens is provided on the object side of the prism and a light focusing lens is required on the image side of the prism in addition to the lens group including the zoom lens unit and the focus lens for unit. Lens was required and there was a limit to miniaturization of the camera.

  Accordingly, an object of the present invention is to provide a camera module with a small number of lenses and capable of further miniaturization, a camera using the camera module, and a mobile phone with a camera.

  The invention according to claim 1 is a prism that reflects light incident from the object side at a predetermined angle and emits the light to the image side, a lens group provided on the image side of the prism, and a surface provided on the image side of the lens group. The prism has a lens function by forming at least one of the object side surface and the image side surface as a curved surface.

  The invention according to claim 2 is the invention according to claim 1, characterized in that the prism has a concave object side surface and a convex image side surface.

  According to a third aspect of the present invention, in the second aspect of the present invention, the lens group includes a zoom lens unit and a focus lens unit, and changes a magnification of an image formed on the imaging body and performs focusing. It is characterized by.

The invention according to claim 4 is the invention according to claim 3, wherein f is the focal length of the entire optical system and the focal length of the prism is f1.
5.6 <(f1) / f <8
It satisfies the following conditions.

According to a fifth aspect of the present invention, in the invention of the fourth aspect, the prism has a length on the optical axis of d1, f is a focal length of the entire optical system, and the connection of the image pickup body from the incident surface of the prism. If the distance to the image plane is T,
1.8 <d1 / f <3
6 <T / f <8
It satisfies the following conditions.

  A sixth aspect of the present invention is a camera comprising the camera module according to any one of the first to fifth aspects.

  A seventh aspect of the present invention is a camera-equipped mobile phone in which the camera according to the sixth aspect is mounted.

  According to the first aspect of the present invention, the prism has a lens function with at least one of the object side surface (incident side surface) and the image side surface (outgoing side surface) as a curved surface. Since an objective lens provided on the side or a lens such as a light focusing lens provided on the image side of the prism can be eliminated, the number of lenses can be reduced, and the thickness of the unnecessary lens and the prism and the unnecessary lens can be reduced. The dimension for the interval is reduced, and the size can be reduced.

  According to the second aspect of the invention, the two effects of the first and second effects can be obtained, and the objective lens disposed on the object side of the prism and the light focusing lens disposed on the image side of the prism. Therefore, these lenses can be reduced and the size can be reduced.

  According to the invention described in claim 3, while the function and effect described in claim 2 can be obtained, the camera module having a zoom function is easily increased in size, but the camera module having the zoom function is reduced in size. be able to.

  According to the invention described in claim 4, the function and effect described in claim 3 can be obtained, and the camera module characteristics of astigmatism, distortion, and spherical aberration can be improved. In other words, 5.6 <(f1) / f <8 is set. When (f1) / f is the lower limit value of 5.6 or less, astigmatism is large on the wide side and is displaced toward the negative side on the periphery. This is because the distortion aberration is greatly displaced toward the + side at the periphery, and the spherical aberration is also largely displaced toward the + side at the same time. Also, if (f1) / f is greater than or equal to the upper limit of 8, the astigmatism is displaced to the + (plus) side, and the spherical aberration is greatly displaced to the-(minus) side, both resulting in poor peripheral resolution. .

  According to the invention described in claim 5, the function and effect described in claim 3 can be obtained, and by setting d1 and f within a predetermined range, the entire module can be obtained without deteriorating the optical specification. Can be minimized, and the distance from the object side surface of the prism to the imaging surface of the imaging body can be reduced.

  According to invention of Claim 6, the camera which can acquire the effect as described in any one of Claims 1-5 can be provided.

  According to the invention described in claim 7, it is possible to provide a camera-equipped mobile phone having the function and effect described in claim 6.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows the configuration of the camera module according to the first embodiment, and is a configuration diagram in a state where the zoom lens unit is at the wide-angle (wide) end position. FIG. FIGS. 3A and 3B show a state where the zoom lens unit is at an intermediate position (normal), FIG. 3B shows a state where the zoom lens unit is at a telephoto (tele) end position, and FIG. 3 shows the first embodiment. 4 is a graph showing camera characteristics when the zoom lens unit is at the wide-angle end position, (a) is a graph of spherical aberration, (b) is a graph of astigmatism, and (c) is a graph of distortion aberration. FIG. 4 is a graph showing camera characteristics when the zoom lens unit is at an intermediate position in the first embodiment, (a) is a graph of spherical aberration, (b) is a graph of astigmatism, ( c) Distortion aberration It is a graph. FIG. 5 is a graph showing camera characteristics when the zoom lens unit is at the telephoto end position in the first embodiment, (a) is a graph of spherical aberration, (b) is a graph of astigmatism, c) is a graph of distortion.

  The camera module 1 according to the first embodiment is a camera module of a camera with a zoom function incorporated in a mobile phone. As shown in FIG. 1, the camera module 1 includes a prism 3, a focus lens unit 5, a zoom lens unit (magnification lens unit) 7, an imaging lens 9, a cover glass 11, and an imaging body in order from the object side to the image side. 13 is arranged.

  The prism 3 reflects incident light on the reflecting surface 3a at an angle of approximately 90 degrees and emits it. The reflection angle of the prism 3 is not limited to 90 degrees, but is preferably 70 degrees to 100 degrees. This is because within this range, the overall length L of the camera module 1 can be made sufficiently smaller than when no prism is used.

  The prism 3 has a first surface (1) that is an object side surface (incident side surface) as a concave surface having a radius R1 that is recessed toward the image side, and a second surface (2) that is an image side surface (outgoing side surface) projects toward the image side. The convex surface has a radius R2. Reference numeral 15 in the zoom lens unit 7 is a stop.

  In the present embodiment, the zoom lens unit 7 and the focus lens unit 5 can have a magnification of 0.146 to 0.438 times, and the zoom ratio is 0.3 to 3 times. The zoom ratio can be set up to about 7 times.

  The imaging lens 9 is a convex lens that protrudes toward the image side, and focuses on the imaging body 13 to form an image.

  The imaging body 13 is an image sensor such as a CCD (Charge Coupled Device) or a C-MOS (Complementary Metal Oxide Semiconductor).

  Table 1 shows the curvature radii of the surfaces of the prism 3 and the constituent members such as the lenses constituting the camera module 1 and the spacing between the surfaces.

ｓは実在絞り面、＊は非球面を示す

s indicates a real diaphragm surface, * indicates an aspherical surface

  In Table 1, the distance between the first surfaces is a distance from the image side surface of the cover glass on the object side (not shown), and the distance shown in the table is the distance from the previous surface.

  Further, when f is the focal length of the entire optical system and the focal length of the entire prism 3 (the focal length combining the first surface (1) and the second surface (2) having a lens function) is f1, Formula 1 is satisfied.

  5.6 <(f1) / f <8 (Formula 1)

  In the first embodiment, f1 is 34.22 mm, and f is shown in Table 2 below. In Table 2, W is the focal length when the zoom lens is at the wide-angle end position, N is the intermediate position, and T is the focal length when it is at the telephoto end position. In addition, F / No. Is the F number.

  The prism 3 satisfies the following formulas 2 and 3 when the length on the optical axis is d1 and the distance from the incident surface of the prism to the imaging surface of the imaging body is T.

1.8 <d1 / f <3 (Formula 2)
6 <T / f <8 (Formula 3)

  In the first embodiment, d1 is 10 mm and T is 32 mm.

  Next, operations and effects of the camera module 1 according to the first embodiment will be described. The prism 3 has both an object side surface (first surface (1)) and an image side surface (second surface (2)) as curved surfaces, and the object side surface (1) is an objective lens conventionally provided on the object side of the prism. Since the image side surface (2) functions as a light focusing lens (convex lens) that is conventionally provided on the object side of the prism, the objective lens and the image that are disposed on the object side of the prism are conventionally provided. The light focusing lens (convex lens) arranged on the side is deleted.

  That is, in the present embodiment, the two lenses conventionally provided on the object side and the image side of the prism can be eliminated, so that the number of lenses can be reduced, and the thickness of the unnecessary lens and the prism are not necessary. Since the dimension corresponding to the distance from the lens is eliminated, the camera module 1 can be reduced in size.

  In the present embodiment, the focus lens unit 5 and the zoom lens unit 7 are provided, and the camera module has a so-called zoom function. However, the camera module 1 having such a zoom function can be downsized.

  Here, in the camera module 1 according to the present embodiment, the camera characteristics of astigmatism, distortion, and spherical aberration were measured, and the results will be described.

  3 shows the zoom lens unit 5 at the wide end position, FIG. 4 shows the normal position (intermediate position between the wide end and the telephoto end), and FIG. 5 shows the telephoto (telephoto end) position. 3 to 5, (a) is a graph of astigmatism, (b) is a graph of distortion, and (c) is a glass of spherical aberration.

  In each measurement, e has a wavelength of 486 nm, f has a wavelength of 546 nm, g has a wavelength of 588 nm, h has a wavelength of 436 nm, and i has a wavelength of 656 nm.

  The image pickup body used 5M pixels.

  As apparent from FIGS. 3 to 5, the spherical aberration is less than 80 μ, the variation in astigmatism is small, the distortion is less than 5%, and good camera characteristics can be obtained.

  Next, a second embodiment will be described. In the first embodiment, in the second embodiment, the curvature radius of each surface of the constituent members such as the prism 3 and the lenses constituting the camera module 1 and the distance between the surfaces are changed. The numerical values are shown in Table 3.

  In the second embodiment, f1 is 42.23 mm in Equation 1 described above, and f is shown in Table 4 below. Moreover, in Formula 2 and Formula 3, d1 was 13.4 mm and T was 36 mm.

ｓは実在絞り面、＊は非球面を示す

s indicates a real diaphragm surface, * indicates an aspherical surface

  In the second embodiment, f1 is 42.23 mm. In Table 2, W is a value when the zoom lens is at the wide-angle end position, N is an intermediate position, and T is a value when it is at the telephoto end position. In addition, F / No. Is the F number.

  In the camera module 1 according to the second embodiment, the camera characteristics of astigmatism, distortion, and spherical aberration were measured, and the results are shown in FIGS. 6 shows the zoom lens unit 5 at the wide end position, FIG. 7 shows the normal position, and FIG. 8 shows the tele position. In each of FIGS. Point aberration graph, (b) is a distortion aberration graph, and (c) is a spherical aberration glass. Each measurement was performed in the same manner as in the first embodiment.

  Also in the second embodiment, as is apparent from FIGS. 6 to 8, the spherical aberration is smaller than 80 μm, the astigmatism is less varied, the distortion is almost smaller than 5%, and the camera characteristics are good. Could get. In FIG. 6C, there is a portion where the distortion aberration is larger than 5%, but it is in a range where there is no problem as a function.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

  For example, the prism 3 is not limited to be provided with a curved surface that imparts a lens function to both the object side surface (first surface (1)) and the image side surface (second surface (2)). A concave curved surface may be provided only on the first surface (1) to eliminate the conventional object lens, or a convex curved surface may be provided only on the image side surface (second surface (2)). In addition, the conventional light focusing lens (convex lens) may be deleted.

FIG. 2 is a configuration diagram illustrating a configuration of a camera module according to an embodiment of the present invention in a state where a zoom lens unit is at a wide end position (wide angle end position). FIG. 2 is a configuration diagram of a camera module according to an embodiment of the present invention, where (a) shows a state where the zoom lens unit is at a normal position (intermediate position), and (b) shows a state where the zoom lens unit is at a telephoto end position. is there. It is a graph which shows a camera characteristic when the camera module which concerns on 1st Embodiment exists in a wide-angle end position, (a) is a graph of spherical aberration, (b) is a graph of astigmatism, (c) is It is a graph of a distortion aberration. It is a graph which shows the camera characteristic when the camera module which concerns on 1st Embodiment is in an intermediate position, (a) is a graph of spherical aberration, (b) is a graph of astigmatism, (c) is a distortion aberration It is a graph of. It is a graph which shows a camera characteristic when the camera module which concerns on 1st Embodiment exists in a telephoto position, (a) is a graph of spherical aberration, (b) is a graph of astigmatism, (c) is a distortion. It is a graph of an aberration. It is a graph which shows a camera characteristic when the camera module which concerns on 2nd Embodiment is in a wide-angle end position, (a) is a graph of spherical aberration, (b) is a graph of astigmatism, (c) is It is a graph of a distortion aberration. It is a graph which shows the camera characteristic when the camera module which concerns on 2nd Embodiment is in an intermediate position, (a) is a graph of spherical aberration, (b) is a graph of astigmatism, (c) is a distortion aberration It is a graph of. It is a graph which shows a camera characteristic when the camera module which concerns on 2nd Embodiment is in a telephoto position, (a) is a graph of spherical aberration, (b) is a graph of astigmatism, (c) is a distortion. It is a graph of an aberration.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Camera module 3 Prism 5 Focus lens unit 7 Zoom lens unit 9 Imaging lens 13 Imaging body (1) Object side surface (1st surface) of prism
(2) Image side of prism (second surface)

Claims (7)

  A prism that reflects light incident from the object side at a predetermined angle and emits the light to the image side, a lens group provided on the image side of the prism, and an imaging body that is provided on the image side of the lens group and forms an image on the surface. The prism module has a lens function by forming at least one of the object side surface and the image side surface as a curved surface.   The camera module according to claim 1, wherein the prism has a concave object side surface and a convex image side surface.   The camera module according to claim 2, wherein the lens group includes a zoom lens unit and a focus lens unit, and performs focusing while changing a magnification of an image formed on the imaging body. When f is the focal length of the entire optical system and the focal length of the prism is f1,
5.6 <(f1) / f <8
The camera module according to claim 3, wherein the following condition is satisfied. When the length of the prism on the optical axis is d1, f is the focal length of the entire optical system, and the distance from the incident surface of the prism to the imaging surface of the imaging body is T,
1.8 <d1 / f <3
6 <T / f <8
The camera module according to claim 4, wherein the following condition is satisfied.   A camera comprising the camera module according to claim 1.   A camera-equipped mobile phone, comprising the camera according to claim 6.

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