JP2005227483A - Imaging lens, and imaging part structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the difference in light quantity between the center part and the peripheral part of an image to be formed on a sensor imaging face by reducing the quantity of light entering the sensor imaging face from the center part of an imaging lens. <P>SOLUTION: An imaging part structure which forms an image of a light beam entering from an object on a sensor imaging face 611 by an imaging lens 205 (lenses, 51, 52, 53) is equipped with a light quantity reducing member 55 which partially reduces the quantity of light entering the sensor imaging face 611 from the imaging lens (lenses, 51, 52, 53). As a result, the quantity of light entering the sensor imaging face 611 is partially reduced by the light quantity reducing member 55. Especially, the quantity of the light entering the imaging face 611 from the center part of the imaging lens 205 is reduced by providing a mask 55 for light shielding at the center part of the imaging lens 205 (lens 52) as the light reducing member. Thus, even when a lens unit is miniaturized, the difference in light quantity between the center part and the peripheral part of the image to be formed on the sensor imaging face 611 is reduced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an imaging lens used in a digital camera and an imaging unit structure including the imaging lens.

In a digital camera, a light beam incident from a lens is focused on a sensor (CCD sensor), and an image is formed (see, for example, Patent Document 1).
By the way, in the sensor, the incident angle differs between the light beam incident on the central portion and the light beam incident on the peripheral portion. The light receiving part of the sensor is composed of a color filter, a light shielding mask, a microlens, etc., and the amount of light received at the central part and the peripheral part varies depending on the angle at which the light beam is incident. The amount of light tends to decrease.
Further, the amount of light at the peripheral portion tends to be halved with respect to the central portion due to the characteristics of the lens.
As described above, a conventional lens unit including a lens and a CCD sensor has a difference of about 40% to 50% in the light amount in the central portion and the light amount in the peripheral portion depending on the sensor light receiving portion characteristics and the lens characteristics. The difference was not anxious in a simple image.
JP 2003-84184 A

However, recently, with the miniaturization of the lens unit, the change in the incident angle to the sensor increases, and the change in the amount of light at the peripheral portion of the lens also tends to become abrupt.
For this reason, even in a general image, there is a problem that the light amount difference between the central portion and the peripheral portion becomes a level that cannot be ignored.

  An object of the present invention is to reduce the amount of light incident on the sensor imaging surface from the central portion of the imaging lens, and to suppress the difference in light amount between the central portion and the peripheral portion of the image formed on the sensor imaging surface.

  In order to solve the above problems, the invention described in claim 1 partially reduces the amount of light incident on the sensor imaging surface 611 from the imaging lens 205 (lenses 51, 52, 53), as shown in FIG. An imaging lens including a light amount reducing member 55 to be used is characterized.

  According to the third aspect of the present invention, for example, as shown in FIG. A light amount reducing member 55 that partially reduces the amount of light incident on the sensor imaging surface 611 from the lens 205 (lenses 51, 52, and 53) is provided.

  According to the first or third aspect of the invention, since the imaging lens or the imaging unit includes the light amount reducing member, the light amount incident on the sensor imaging surface from the imaging lens can be partially reduced by the light amount reducing member.

  Invention of Claim 2 or 4 is the imaging lens of Claim 1, or the imaging part structure of Claim 3, Comprising: For example, as shown in FIG. A light shielding mask 55 is provided at the center of the (lens 52).

According to the invention described in claim 2 or 4, since the light shielding mask is provided in the central portion of the imaging lens, the amount of light incident on the sensor imaging surface from the central portion of the lens can be reduced.
As a result, even when the lens unit is downsized, the difference in light amount between the central portion and the peripheral portion of the image formed on the sensor imaging surface can be suppressed.

According to the present invention, the amount of light incident on the sensor imaging surface from the imaging lens can be partially reduced by the light amount reducing member.
In particular, by providing a light shielding mask at the center of the imaging lens, the amount of light incident on the sensor imaging surface from the center of the lens can be reduced.
Therefore, even when the lens unit is downsized, it is possible to provide a good image by suppressing the difference in light quantity between the central portion and the peripheral portion of the image formed on the sensor imaging surface.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.
In FIG. 1 (a is a front view in an opened state and (b) is a rear view in the same state) showing a foldable mobile phone as an embodiment to which the present invention is applied, It is a lid.
The main unit 1 includes an antenna 101, a camera key 102, a mail key 103, a cross key 104, an enter key 105, an address book key 106, a net connection key 107, a clear key 108, an on-hook key 109, an off-hook key 111, a numeric key 112, and a microphone. 113, a card slot cover 114, a notification speaker sound emitting unit 115, a battery pack 116, a charging terminal 117, a USB terminal 118, a connector cover 119, and the like.
The lid 2 includes a speaker 201, a main display unit 202, a sub display unit 203, a notification LED 204, an imaging lens 205, a flash LED 206, and the like.

  As shown in FIG. 2, the lid 2 is composed of a lower case 21, an intermediate case 22, an upper case 23, a hinge piece 24, a decorative panel 26, a receiver cover 27, a logo plate 28, and the like. In the figure, 30 is a middle case assembly, 210 is a case screw, 212 is a main display panel, 213 is a sub display panel, 215 is a lens cover, 216 is an LED cover, 220, 230 and 240 are cushions, 225 is a lens panel, 232 233, 235, 236, 271 and 281 are double-sided tapes.

As shown in an enlarged view in FIG. 3, the middle case assembly 30 is obtained by incorporating the sub display unit 203, the shield case 31, the camera module 32, the sub circuit board 33, and the like into the middle case 22.
That is, the liquid crystal display substrate (not shown) of the main display unit 202 and the liquid crystal display substrate 311 of the sub display unit 203 are incorporated in the shield case 31 back to back. The shield case 31 is housed and fixed in the middle case 22 so that the main display unit 202 and the sub display unit 203 are exposed on the front and back surfaces of the middle case 22, respectively.
A camera module storage portion 221 is formed on one end side in the longitudinal direction with the sub display portion 203 of the middle case 22 as a reference, and a storage opening portion 222 for an incoming call notification LED unit (not shown) is formed on the other end side. Has been.

The camera module 32 is obtained by mounting and fixing a unit case 321 incorporating an imaging lens 205, a flash LED 206, and an AF motor 207 using a step motor to a circuit board 322 such as a lens. On the circuit board 322 such as a lens, as shown in FIG. 4, electronic components are mounted and heat seals 323 324 325 are provided.
The sub circuit board 33 is attached and fixed to the surface opposite to the shield case 31 with respect to the middle case 22 and has a shape in which the sub display unit 203 is disposed in the opening 337 and the camera module 32 is disposed in the opening 338. As shown in the figure, electronic components are mounted on the sub-circuit board 33. Specifically, liquid crystal drivers 331, 332, 333, camera control components 334, 335, and the like are mounted. Here, the liquid crystal drivers 331, 332, and 333 and the camera control components 334 and 335 have an arrangement structure that faces each other with the sub display unit 203 interposed therebetween. A camera control circuit 336 including camera control components 334 and 335 is configured.

The camera module 32 is assembled to the sub circuit board 33 so as to be disposed in the opening 338 by connecting heat seals 323 and 325 as shown in FIG.
The sub circuit board 33 assembled with the camera module 32 is attached and fixed to the surface opposite to the shield case 31 with respect to the middle case 22 as shown in FIG. As illustrated, heat seals 312 and 313 extending from the liquid crystal display substrate 311 and the like are connected to the liquid crystal drivers 331, 332, and 333.
Then, as shown in FIG. 2, the middle case assembly 30 is sandwiched between the lower case 21 and the upper case 23 and fixed by the case screws 210, and the decorative panel 26 is attached to the surface of the lower case 21.

  In the above mobile phone, the camera unit including the imaging lens 205 and the like of the camera module 32 has a configuration described below.

  In FIG. 1 showing an imaging lens and an imaging element portion of a camera unit as a configuration of an imaging unit structure to which the present invention is applied, 50 is a lens frame, 51, 52 and 53 are imaging lenses, and 55 is a light shielding mask. (Light quantity reducing member), 61 is a CCD (imaging device), and 62 is a lens fixing frame.

In the embodiment, as shown in the figure, a lens fixing frame 62 is provided in a CCD 61 that is an imaging device, and the lens fixing frame 62 includes a lens frame 50 including an imaging lens 205 positioned on the optical path to the CCD sensor imaging surface 611. Are assembled so as to be freely extended by screw connection. The imaging lens 205 includes three lenses 51, 52, and 53.
A light shielding mask 55 is attached as a light amount reducing member to the center of the convex surface of the second lens 52 facing the CCD 61.

In the above imaging unit structure, the light beam incident from the subject is imaged on the CCD sensor imaging surface 611 by the imaging lens 205.
Therefore, the problem of the response to the change in the incident angle of the micro lens of the CCD 61 due to the increase in the incident angle of the light beam on the CCD sensor imaging surface 611, that is, the brightness of the central portion relative to the peripheral portion in the CCD sensor imaging surface 611 If this embodiment of applying a light shielding mask 55 to the central portion of the convex surface of the intermediate lens 52 of the imaging lens 205 toward the CCD 61 is applied to the problem that the image is too conspicuous (virtual line portion), The amount of light reaching the center of the CCD sensor imaging surface 611 can be halved by cutting the amount of light at the center.

  The location, transmittance, and shape of the light-shielding mask 55 differ depending on the optical characteristics of the imaging lens and the characteristics of the CCD, so the optimum position, transmittance, and shape differ depending on the individual lens specifications. .

As described above, in the embodiment, the camera of the mobile phone has a structure in which the light-shielding mask 55 is attached to the center of the intermediate lens 52 of the imaging lens 205.
According to such an imaging unit structure, the light amount at the center is cut by the light shielding mask 55 attached to the center of the intermediate lens 52 of the imaging lens 205 and reaches the center of the CCD sensor imaging surface 611. The amount of light can be halved.
Therefore, it is possible to adjust and suppress the difference in light amount between the central portion and the peripheral portion of the image formed on the CCD sensor imaging surface 611, so that even when the lens unit is miniaturized in the camera of the mobile phone, it is good. Images can be provided.

In the above embodiment, the present invention is applied to a foldable mobile phone. However, the application of the present invention is not limited to this, and may be another mobile communication device, a mobile electronic device, or a digital camera.
In the embodiment, the light amount reducing member is a light shielding mask provided at the center of the second lens among the plurality of imaging lenses. However, the present invention is limited to the light shielding mask. is not. For example, anything may be used as long as it has a function of reducing the amount of light, it may be provided in any lens, and further, it may be arranged on the optical path without being attached to the lens. In this embodiment, a member called a light shielding mask is used as the light quantity reducing member. However, a paint having a light quantity reducing function may be directly applied to the lens, and the lens itself has normal optical characteristics. You may comprise by the two-color shaping | molding of a member and the member which has a light quantity reduction function.
Furthermore, the image pickup device is not limited to the CCD, but may be a CMOS image sensor or other specific details such as a single image pickup lens. .

It is the front view (a) and the rear view (b) which show the state which opened the foldable mobile telephone as one Embodiment to which this invention is applied. FIG. 2 is an exploded perspective view showing an upper case, an intermediate case, a lower case, a decorative panel, and the like constituting a lid portion of the foldable mobile phone of FIG. 1. It is a disassembled perspective view of the middle case assembly of FIG. FIG. 4 is a plan view showing how to connect the camera module of FIG. 3 and a substrate. BRIEF DESCRIPTION OF THE DRAWINGS It is the center longitudinal cross-sectional view which showed the structure of one Embodiment of the imaging part structure to which this invention is applied, and showed the imaging lens and imaging device part of a camera part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main-body part 2 Cover part 205 Imaging lens 50 Mirror frame 51 * 52 * 53 Lens 55 Shading mask (light quantity reduction member)
61 Image sensor 611 Sensor imaging surface 62 Lens fixing frame

Claims (4)

  An imaging lens comprising: a light amount reducing member that partially reduces a light amount incident on a sensor imaging surface from the imaging lens.   The imaging lens according to claim 1, wherein a light shielding mask is provided at a central portion of the lens as the light amount reducing member. In the imaging unit structure that forms an image on the sensor imaging surface of the light beam incident from the subject by the imaging lens,
An image pickup unit structure comprising a light amount reduction member that partially reduces the amount of light incident on the sensor image pickup surface from the image pickup lens.   The imaging unit structure according to claim 3, wherein a light-shielding mask is provided at a central portion of the imaging lens as the light amount reducing member.

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