KR20170059552A

KR20170059552A - Optical filter and camera module using thereof

Info

Publication number: KR20170059552A
Application number: KR1020150163636A
Authority: KR
Inventors: 윤수영
Original assignee: 윤수영
Priority date: 2015-11-21
Filing date: 2015-11-21
Publication date: 2017-05-31

Abstract

The optical filter according to the present invention comprises a first film layer formed on a part of the center aligned with an optical axis for transmitting infrared light and a second film layer formed on a part of the surface on which the first film layer is formed, And a second film layer for blocking the infrared band light. According to another embodiment of the present invention, there is provided an optical filter comprising: a first film layer formed on a part of the center aligned with an optical axis of one side and transmitting infrared band light; and a second film layer formed on the first side of the first film layer, And a second film layer formed on the remaining portion except the portion corresponding to the film layer.

Description

TECHNICAL FIELD [0001] The present invention relates to an optical filter and a camera module including the optical filter.

The present invention relates to a camera module, and more particularly, to a camera module capable of using light in an infrared wavelength band and a visible light wavelength band at the same time.

An infrared camera is used to obtain image information from a subject that is used as a means for acquiring image information in a dark environment or difficult to visually recognize by a human being, or as a means for confirming the thermal characteristic of the subject or a security surveillance camera or non-destructive It is widely used for various purposes such as inspection cameras.

A technology relating to an apparatus for securing image information in a dark environment by using the above-described infrared rays is called night vision, and is described in detail in Korean Patent Registration Nos. 10-0955975 and 10-0649954. Reference is made to the above-mentioned Patent No. 10-0955975, which can not be used as a camera for securing image information from light in a general visible band as a device using a special material lens for transmitting light in an infrared wavelength band.

The infrared camera described above may be used as a camera module for biometric recognition such as iris recognition and vein recognition in addition to the night vision described above. Among the domestic patents related to a camera having iris recognition function, Japanese Patent No. 10-0673427 A portable communication terminal having an iris recognition function), and Japanese Laid-Open Patent Application No. 10-2012-0068655. 10-0673427 should further include a complicated driving part for selectively applying the near-infrared ray blocking filter and the near-infrared ray transmitting filter.

Conventional infrared cameras use a special material having a high light transmittance in the infrared band or use an IR band pass filter capable of transmitting light in an infrared band to an ordinary camera used in the visible light band There are a variety of ways. That is, conventional camera devices using infrared band light can not simultaneously acquire images that can be recognized by a general person using visible light, or they must include a complicated mechanical structure to secure the images at the same time.

Particularly, in recent years, due to development of financial services using portable communication terminals such as smart phones, the demand for compact infrared cameras suitable for miniaturized electronic devices is increasing.

However, conventionally, in addition to a general camera module for photographing an image of a visible light band, an infrared camera for photographing an image of an infrared wavelength band is additionally employed, or an IR bandpass filter There is a problem that it is necessary to further include a complicated device such as mechanically driving an IR cut filter and an IR cut filter. That is, a conventional camera module using infrared light has a problem that it is not suitable for a portable communication terminal (portable electronic device) which is expensive or requires a complicated structure and thinness.

An object of the present invention is to provide a camera module which can be manufactured at a lower cost than the conventional one, thin at the same time, and can simultaneously process an infrared band image and a visible light band image information.

According to an embodiment of the present invention,

An optical filter including a pin-hole area formed in a portion corresponding to an optical axis of a surface facing the image sensor; An image sensor arranged opposite to the pin-hole area side; An IR band-pass filter is formed on a surface of the optical filter facing the object side, and an infrared band-pass filter is formed on a surface of the optical filter, An IR cut filter is formed in an area other than the pin-hole area.

The present invention relates to an optical filter capable of separating and passing infrared rays and visible rays at the same time, and a camera module including the same, wherein the image information of the visible light band and the infrared band image information can be obtained without any additional configuration or complicated configuration .

That is, in order to secure infrared image information, infrared band image information and visible light band image information can be obtained at the same time without further including an infrared camera module in addition to a general camera module. Further, in order to obtain the infrared band and the visible band image information, it is not necessary to include a separate component for photographing the subject or changing the position of each filter. Furthermore, the present invention can provide the same transmittance as when applying each filter even though one optical filter is used by spatially separating infrared light and visible light with one optical filter.

Therefore, the camera module according to the present invention can be manufactured in a simple and thin structure compared to the conventional infrared camera, thereby reducing the production cost.

1 is a view for explaining an optical filter according to a first embodiment of the present invention,
2 is a view for explaining an optical filter according to a second embodiment of the present invention,
3 is a schematic view of a camera module according to a third embodiment of the present invention,
4 is a view schematically showing a camera module according to a fourth embodiment of the present invention;

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The terms used in the various embodiments of the present invention have selected the general terms that are currently widely available, taking into account the functionality in the various embodiments of the present invention, but are not intended to limit the scope of the present invention, And the like. Also, in certain cases, some terms are arbitrarily selected by the applicant, and the meaning thereof will be described in detail in the description of the various embodiments of the present invention. Therefore, the terms used in various embodiments of the present invention should not be construed to be mere terms, but rather should be defined based on the meaning of the terms and throughout the various embodiments of the present invention.

Also, terms including ordinal numbers such as first, second, etc. may be used to describe various elements, but the elements are not limited to these terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

1 is a view of an optical filter according to a first embodiment of the present invention. 1, an optical filter 100 according to the present invention includes a filter used as an IR cut filter in a camera module, an IR band pass filter (not shown) capable of transmitting light of a wavelength selected in the infrared wavelength band, (IR band pass filter). That is, the optical filter 100 according to the present invention can provide an integrated IR cut filter and an IR band pass filter.

An optical filter 100 according to the present invention includes a substrate 101, a first film layer 110 formed on a portion corresponding to the optical axis O on the first surface 101a, The second film layer 110 is disposed around the first film layer 110 to block light in a wavelength band passing through the first film layer 110 and to transmit light in a wavelength range blocked by the first film layer 110, Film layer 120 and a third film 101b which can transmit a wide band of light from a visible light band to an infrared ray band on a second surface 101b which is opposite to the first surface 101a, Layer 130 may be further included.

The first film layer 110 transmits light in an infrared (IR) wavelength band while blocking light in a visible light band. The first film layer 110 is formed at a portion of the center corresponding to the optical axis, so that light in an infrared wavelength band incident on the first film layer 110 passes through the optical filter 100 along an optical axis. The first film layer 110 is preferably formed at a central portion corresponding to the optical axis, but in some cases, the first film layer 110 may be located in another region other than the optical axis (an area other than the optical axis corresponding to the pixel region of the unused image sensor) .

The second film layer 120 surrounds the periphery of the first film layer 110 in a region other than the first film layer 110 of the first surface 101a that is the same as the first film layer 110 . The second film layer 120 shields light having a wavelength band equal to the wavelength band of the light passing through the first film layer 110 but blocks light in the visible band blocked by the first film layer 110 . In other words, since the first film layer 110 and the second film layer 120 provide optical characteristics opposite to each other, the optical filter 100 according to the present invention is a single integrated structure in which the light in the infrared wavelength band It is possible to simultaneously transmit light in the visible wavelength band.

The third film layer 130 is formed on the second surface 101b and can pass both the light in the visible band and the light in the infrared band. The third film layer 130 preferably functions as an anti-reflection coating having a transmittance as high as possible in a full wavelength band. When the third film layer 130 is formed, the optical filter 100 is preferably disposed such that the third film layer 130 faces the subject side. However, The optical filter 100 can be aligned such that either the first surface or the second surface faces the object side. The optical filter 100 may be configured without including the third film layer 130.

For example, iris recognition can be used for any wavelength of light in the wavelength band between 700 nm and 1000 nm, but it can be limited to use due to noise due to light in the visible light band at 750 nm or less, It can not be separated and can be limited in use. On the other hand, light between 800 and 900 nm is easy to apply iris recognition without the above-mentioned problem. The second film layer 120 functions as an IR cut filter that transmits only light in a visible wavelength band between 380 and 700 nm and blocks light in an infrared wavelength band between 700 and 1000 nm. On the other hand, the first film layer 110 provides a function of an IR band pass filter for passing only light in the infrared wavelength band. However, the first film layer 110 does not use all the light in the infrared wavelength band, but only the necessary wavelength of the infrared wavelength band can be transmitted as necessary. As described above, the first film layer 110 can select light of a specific wavelength and its band width in the entire infrared wavelength band depending on the use of the optical filter 100, if necessary.

The light incident on the optical axis of the optical system travels only along the optical axis without being diffused to the peripheral portion, so that only the pixel (one point) located on the optical axis is used when viewed from the image sensor (or film) side. On the other hand, light in the visible light band incident on the periphery of the optical axis is incident on all the remaining pixels of the image sensor, and can be provided with normal image information that the user can recognize with the naked eye.

That is, according to the present invention, the second film layer 120 transmits only the visible light, cuts off the infrared wavelength band, and the first film layer 110 transmits the infrared band light incident along the optical axis It is possible to simultaneously provide the two opposite functions of the IR cut filter and the IR band pass filter with one filter.

Accordingly, the present invention provides a security device using biometric information such as nondestructive inspection using infrared rays, iris recognition, and infrared information and visible light such as photographing of subject information in a dark environment which can not be confirmed only by a human's naked eye (naked eye without naked eye) Band video information can be applied to all equipment that need to use simultaneously. As described above, the light that the first film layer 110 can pass through can be selected according to the use thereof.

FIG. 2 is a view for explaining another structure of the optical filter 100 according to the second embodiment of the present invention. Referring to FIG. 2, in the optical filter 100 according to the present embodiment, the first film layer 110 and the second film layer 120 are disposed on different surfaces. The first film layer 110 is positioned at a central portion corresponding to the optical axis O of the first surface 101a and the second film layer 110b of the second surface 101b, which is the opposite surface of the first surface 101a, The second film layer 120 is positioned on the remaining portion except for the portion corresponding to the first film layer 110. The first film layer 110 transmits only light in the infrared wavelength band and the second film layer 120 shields infrared light in the wavelength band that the first film layer passes and transmits light in the visible light band .

Although it is preferable that the first film layer 110 and the second film layer 120 are disposed on the same plane as described in the first embodiment of FIG. 1, The first film layer 110 and the second film layer 120 may be disposed. However, in the case of the structure of Fig. 2, it is particularly preferable that the first surface 101a is positioned so as to directly face the image sensor side. The first film layer 110 may be formed to have the same area as or larger than a portion where the second film layer 120 is not formed.

FIG. 3 is a diagram showing a schematic structure of a camera module according to a third embodiment of the present invention. The optical filter 100 shown in FIG. 3 is similar to that described in FIG. 1 and FIG. The camera module according to the present embodiment includes an optical filter 100 capable of simultaneously transmitting and blocking light in an infrared wavelength band, an image sensor 300 arranged in parallel with the optical filter 100 on the optical axis, And a lens group 200 for providing the image sensor with light incident thereon.

The optical filter 100 includes a first film layer 110 formed to transmit or shield predetermined wavelength band light to a first surface 101a opposed to a subject and a second film layer 110 formed on the first surface 101a, And a second film layer 120 formed in an area other than the film layer 110 and may further include a third film layer 130 for providing an anti-reflection function on the second surface 101b Lt; / RTI > The optical filter 100 may have a structure in which a first film layer 110 is formed on a first surface and a second film layer 120 is formed on a second surface, as shown in FIG.

The first film layer 110 is arranged on the optical axis and transmits infrared band wavelength light incident along the optical axis, and the infrared wavelength band light incident on the first film layer 110 passes through the lens group 200, and is then incident on the image sensor 300. The light incident on the optical axis is incident on the pixel of the image sensor 300 corresponding to the optical axis O, and then the image information of the infrared wavelength band reflected from the subject is provided to the user through the camera module. That is, the present invention can be applied to a case in which infrared wavelength band light is incident along an optical axis and visible light wavelength band light that can be perceived by the human eye is incident on the peripheral portion of the other optical axis to use different wavelength bands . Although the first film layer 110 is described as a position corresponding to the optical axis, it may be formed at a position other than the optical axis in accordance with the characteristics of the optical system (the range of the image sensor, the angle of view, and the like).

The camera module according to the present embodiment uses the optical filter 100 in which the IR cut filter and the IR band pass filter are integrated to reduce the space for each of the IR cut filter and the IR band pass filter, It is not necessary to include a driving unit for positioning the filters alternately on the optical axis, so that the production is easy and the production cost can be reduced. Furthermore, the camera module according to the present embodiment can be applied to all the conventional camera modules, and besides, it is not necessary to apply the driving part for the filter, so that the consumption current to be used can be minimized. In addition, the present invention can acquire information using two different wavelengths by using only one camera without using an infrared camera and a general camera separately.

In the camera module according to the present embodiment, the first surface 101a on which the first film layer 110 is formed is disposed opposite to the image sensor 300, but the first film layer 110 May be applied to a structure in which the second surface 101b, which is the other side of the surface on which the first lens 101 is formed, is arranged to face the subject side.

3 is a structure in which the lens group 200 is positioned between the optical filter 100 and the image sensor 300 so that the optical filter 100 is directly opposed to the subject, The embodiment is a view for explaining a structure in which the optical filter 100 is positioned between the lens group 200 and the image sensor 300.

As the distance between the first film layer 110 and the image sensor 300 is narrowed, the light incident on the first film layer 110 is incident on the other side of the image sensor 300 (other than the pixel positioned on the optical axis) It can be incident only on the pixel corresponding to the optical axis without diffusing into the pixel. An ordinary lens has a curvature, but the center portion aligned with the optical axis is a point, and light incident on the optical axis goes straight along the optical axis.

The camera module shown in FIG. 4 includes a lens group 200 and an image sensor 300 such that the surface of the optical filter 100 on which the first film layer 110 and the second film layer 120 are formed, The optical filter 100 is positioned. The optical filter 100 may be attached to the image sensor such that the first and second film layers 110 and 120 are in close contact with the facing surface of the image sensor 300. [ 4 illustrates that the first and second film layers 110 and 120 are shown facing the image sensor 300 but the opposite side of the surface on which the first and second film layers 110 and 120 are formed, Or may be arranged to face the sensor 300.

The optical filter 100 described with reference to FIGS. 1 to 4 may be formed by a method such as etching after deposition of a plurality of dielectric thin films, but may also be made of a material whose optical characteristic is changed by an external power source such as a liquid crystal glass . In the case of a liquid crystal glass, desired wavelength bands may be selected by differently controlling the first film layer 110 and the second film layer 120.

Although the present invention has been described with respect to one optical filter capable of obtaining an image from visible light and infrared light by separating the infrared light and visible light from each other, in order to simultaneously obtain image information from ultraviolet light and general visible light, . &Lt; / RTI > In other words, when ultraviolet light and visible light, which are not infrared rays, are simultaneously used, the first film layer 110 provides a function of passing only light in the ultraviolet wavelength band, unlike the case described with reference to FIGS. 1 to 3, The layer 120 can block light in the ultraviolet wavelength band and pass only the light in the visible light band. In this case, each image information can be obtained from ultraviolet light and visible light with one optical filter.

The optical filter according to the present invention includes a first film layer 110 and a second film layer 120 capable of blocking light in a wavelength band equal to the wavelength transmitted by the first film layer 110, The paths formed on the opposite surfaces are formed so as not to overlap with each other, so that the path along which the lights of different wavelength bands travel can be separated, thereby separating the paths of the two wavelength bands by one optical filter.

100 Optical filter 101 Substrate 101a First surface 101b Second surface
110 First film layer 120 Second film layer 130 Third film layer
200 Lens 300 Image Sensor

Claims

A camera module comprising:
An optical filter including a first film layer for transmitting infrared band light to a part of a center corresponding to an optical axis of one surface and a second film layer formed around the first film layer;
An image sensor arranged to face the optical filter along an optical axis;
And a lens group positioned between the optical filter and the image sensor or between the subject and the optical filter.

The method according to claim 1,
Wherein the second film layer blocks the infrared wavelength band light and transmits the visible light band light.

The optical filter according to claim 1,
And a third film layer formed on an opposite surface of the second film layer to transmit light from a visible light wavelength band to an infrared wavelength band.

The method according to claim 1,
Wherein the optical filter is disposed such that a face on which the first film layer is formed faces the image sensor side or a face opposite to the face on which the first film layer is formed faces the image sensor side. .

A first film layer formed on a portion of the center aligned with the optical axis to transmit infrared light;
And a second film layer formed on the other side of the first film layer on the same side as the first film layer or on the opposite side of the first film layer.

6. The optical filter according to claim 5,
And a third film layer formed on an opposite surface of the second film layer, the third film layer transmitting light from a visible light band to an infrared ray band.

6. The method of claim 5,
Wherein the first film layer transmits visible light.

A first film layer;
A second film layer formed on another surface of the first film layer opposite to the first film layer or on a surface opposite to the first film layer, the second film layer blocking light in a wavelength band equal to a wavelength transmitted by the first film layer, Including an optical filter.