JP2006154573A - Imaging apparatus, electronic device and focusing method in imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus which performs focusing without generating optical axis slippage, an electronic device and a focusing method in the imaging apparatus. <P>SOLUTION: The imaging apparatus 1 has lenses 2, 3, a lens barrel 4 which holds the lenses 2, 3, a holder 5 which holds the lens barrel 4, an imaging device 6, a plurality of prisms 11, 12 provided between the lenses 2, 3 and the imaging device 6 and which can change thickness of the prisms on an optical axis and energization members 9, 10 which apply force along the optical axis direction to the plurality of prisms 11, 12. The imaging apparatus has an actuator 14 which transfers the plurality of prisms 11, 12 in the perpendicular direction to the optical axis and the second prism 12 moves along an inclined plane 11a of the first prism 11. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an imaging apparatus, an electronic apparatus, and a focus adjustment method in the imaging apparatus.

  In conventional cameras and the like, a method for adjusting the focus by moving a lens has been proposed. The following are proposed as such conventional techniques.

  The device described in Patent Document 1 adjusts the focus by moving a lens by a stepping motor.

  The device described in Patent Document 2 moves the relative positions of the prisms formed by joining a plurality of prisms along the joined surface, and sets the optical path length of light passing through each image forming unit and the prism. After adjustment, these prisms are attached with an adhesive.

JP-A-8-15598 JP 9-21209 A

  However, the focus adjustment method described in Patent Document 1 has a problem that an optical axis shift occurs during lens movement. In addition, the device described in Patent Document 2 solves problems such as image distortion due to position error in a part of each component, such as when an optical component is attached, when an impact is applied, or when the temperature changes. When the lens is moved and the focus is adjusted, there is a problem that the optical axis shifts due to the movement of the lens.

  Therefore, the present invention has been made in view of the above problems, and provides an imaging apparatus, an electronic apparatus, and a focus adjustment method in the imaging apparatus that can adjust the focus without causing an optical axis shift due to the movement of the lens. With the goal.

  In order to solve the above-described problems, the present invention provides a plurality of prisms provided between a lens and an image sensor and capable of changing the thickness of the prism on the optical axis, and at least of the plurality of prisms. And an actuator that changes the thickness of the prism on the optical axis by applying a force perpendicular to the optical axis to one. According to the present invention, a force perpendicular to the optical axis is applied to the prism to change the thickness of the prism on the optical axis, so that the optical axis is not shifted due to the movement of the lens, and the focus is not increased. Adjustments can be made.

  The imaging apparatus of the present invention further includes a biasing member that applies a force along the direction of the optical axis to at least one of the plurality of prisms. According to the present invention, the thickness of the prism on the optical axis can be changed by applying a force along the direction of the optical axis to the prism.

  The imaging device of the present invention further includes an optical filter attached to at least one of the plurality of prisms. According to the present invention, it is not necessary to provide a separate optical filter.

  The imaging apparatus of the present invention further includes a control unit that controls the actuator based on an electrical signal converted by the imaging element. According to the present invention, the focus can be automatically adjusted by controlling the actuator based on the electrical signal converted by the imaging device.

  The plurality of prisms include a first prism having an inclined surface inclined with respect to the optical axis, and a second prism that moves along the inclined surface of the first prism. According to the present invention, the thickness of the prism on the optical axis can be changed by moving the second prism along the inclined surface of the first prism.

  The imaging device of the present invention further includes a lens barrel that holds the lens, and a holder that holds the plurality of prisms and holds the lens barrel.

  The present invention is an electronic apparatus including the imaging device. According to the present invention, by changing the thickness of the prism on the optical axis, it is possible to provide an electronic device such as a portable terminal that can adjust the focus without causing an optical axis shift.

  The present invention is a focus adjustment method in an imaging apparatus, and by applying a force in a direction perpendicular to the optical axis to at least one of a plurality of prisms provided between a lens and an imaging element, Changing the thickness of the prism on the optical axis. According to the present invention, focus adjustment can be performed without causing optical axis deviation by changing the thickness of the prism on the optical axis by applying a force perpendicular to the optical axis to the prism. Can do.

  In the step, the second prism different from the first prism is moved on the optical axis along an inclined surface inclined with respect to the optical axis of the first prism among the plurality of prisms. It is preferable to change the thickness of the prism.

  ADVANTAGE OF THE INVENTION According to this invention, the focus adjustment method in an imaging device, an electronic device, and an imaging device which can adjust a focus, without producing the optical axis shift by the movement of a lens can be provided.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of an imaging apparatus according to the present invention. As shown in FIG. 1, the imaging device 1 includes lenses 2 and 3, a lens barrel 4, a holder 5, an imaging device 6, bases 7 and 8, biasing members 9 and 10, a first prism 11, and a second prism. A prism 12, a moving member 13, and an actuator 14 are provided. The imaging device 1 is provided in an electronic device such as a mobile terminal.

  The lens barrel 4 holds the lenses 2 and 3 and is attached to the holder 5 via a screw portion 4a. The holder 5 has a screw portion 5 a that fits with the screw portion 4 a of the lens barrel 4, holds the lens barrel 4, and accommodates the first prism 11, the second prism 12, and the like. Inside the holder 5, in addition to the holder 5, an image sensor 6, bases 7 and 8, biasing members 9 and 10, a first prism 11 and a second prism 12 are arranged. Although not shown, a substrate is present below the holder 5.

  The image sensor 6 is mounted on a substrate. The pedestals 7 and 8 are for supporting the first prism 11 and the second prism 12. The urging members 9 and 10 are configured by, for example, a leaf spring, and apply an upward force along the direction of the optical axis S to the second prism 12.

  The first prism 11 and the second prism 12 are made of glass, for example, and have a triangular shape here. The first prism 11 and the second prism 12 are provided between the lenses 2 and 3 and the image sensor 6, and the thickness of the prism on the optical axis S can be changed depending on the positional relationship. Here, the first prism 11 has an inclined surface 11 a inclined with respect to the optical axis S and is fixed to the holder 5. The second prism 12 moves along the inclined surface 11 a of the first prism 11. Further, it is preferable to attach an optical filter such as an IR cut filter to the first prism 11. This eliminates the need for a separate optical filter.

  The moving member 13 is driven by the actuator 14 to move the second prism 12 left and right. The actuator 14 is composed of, for example, a piezoelectric element or a solenoid, and applies a force in a direction perpendicular to the optical axis S to the second prism 12. The actuator 14 applies a force perpendicular to the optical axis S to the second prism 12 by moving the moving member 13 in the left-right direction in the drawing.

  FIG. 2 is a diagram illustrating a state after movement of the prism in the optical apparatus of the present invention. Here, if the thickness of the medium having the refractive index n is increased by ΔL, the focal position moves by ΔL (1-1 / n) toward the image sensor 6 side. This is the same as moving the lens toward the image sensor 6 by ΔL (1-1 / n). As shown in FIG. 2, when the moving member 13 moves leftward in the figure by the actuator 14, the second prism 12 is moved leftward in the figure as the moving member 13 moves. At this time, the second prism 12 exerts a force upward in the drawing by the urging members 9 and 10, so the second prism 12 is diagonally left in the drawing along the inclined surface 11 a of the first prism 11. Move to. Accordingly, as shown in FIG. 2, the prism thickness on the optical axis can be changed by ΔL as shown in FIGS.

  Thereby, the focus adjustment can be performed without moving the lenses 2 and 3 by changing the thickness of the prism on the optical axis S by the first prism 11 and the second prism 12.

  FIG. 3 is a diagram for explaining the focus adjustment method of the imaging apparatus according to the present invention. As illustrated in FIG. 3, the imaging device 1 further includes a control unit 15. The control unit 15 checks whether or not the image is in focus based on an electric signal obtained by converting the light received by the image sensor 6 and controls the actuator 14 as necessary.

  When the moving member 13 shown in FIG. 1 is moved by driving the actuator 14, a force perpendicular to the optical axis S is applied to the second prism 12. Further, the second prism 12 is moved upward and obliquely along the inclined surface 11 a of the first prism 11 by applying an upward force in the drawing by the urging members 9 and 10. The control unit 15 finishes driving the actuator 14 when the focus is achieved. Accordingly, the focal length is changed by changing the thickness of the prism on the optical axis, so that the focus can be adjusted. Since there is no need to move the lenses 2 and 3, there is no optical axis misalignment. Further, since a lens driving mechanism is not required, the image pickup apparatus can be made small, and the number of assembling steps can be reduced.

  The present invention is not limited to these, and various modifications of these embodiments are within the scope of the present invention, and various other embodiments are possible within the scope of the present invention. It is obvious from the above description. In the above embodiment, an example in which two prisms are used has been described. However, the prism thickness on the optical axis may be changed using more prisms. The optical filter may be attached to any one of the plurality of prisms. Examples of the electronic device include a camera and a mobile terminal.

It is a figure which shows the structure of the imaging device of this invention. It is a figure which shows the state after the movement of the prism in the imaging device of this invention. It is a figure for demonstrating the focus adjustment method of the imaging device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Imaging device 2, 3 Lens 4 Lens barrel 5 Holder 6 Imaging element 7, 8 Pedestal 9, 10 Energizing member 11 1st prism 12 2nd prism 13 Moving member 14 Actuator 15 Control part

Claims (9)

A plurality of prisms provided between the lens and the image sensor and capable of changing the thickness of the prism on the optical axis;
An imaging apparatus comprising: an actuator that changes a thickness of the prism on the optical axis by applying a force in a direction perpendicular to the optical axis to at least one of the plurality of prisms. . The imaging apparatus according to claim 1, further comprising an urging member that applies a force along the direction of the optical axis to at least one of the plurality of prisms. The imaging apparatus according to claim 1, further comprising an optical filter attached to at least one of the plurality of prisms. The imaging apparatus according to any one of claims 1 to 3, further comprising a control unit that controls the actuator based on an electrical signal converted by the imaging element. The plurality of prisms include a first prism having an inclined surface inclined with respect to the optical axis;
5. The imaging apparatus according to claim 1, further comprising: a second prism that moves along the inclined surface of the first prism. A lens barrel for holding the lens;
A holder for housing the plurality of prisms and holding the lens barrel;
The imaging apparatus according to claim 1, further comprising an imaging element. The electronic device provided with the imaging device as described in any one of Claims 1-6. A focus adjustment method in an imaging apparatus,
Changing the thickness of the prism on the optical axis by applying a force in a direction perpendicular to the optical axis to at least one of the plurality of prisms provided between the lens and the image sensor. Focus adjustment method characterized by the above. In the step, the second prism different from the first prism is moved on the optical axis along an inclined surface inclined with respect to the optical axis of the first prism among the plurality of prisms. The focus adjustment method according to claim 8, wherein the thickness of the prism is changed.

Images