KR101056168B1 - Camera module and portable terminal having same - Google Patents

Abstract

The present invention is capable of maintaining color reproducibility in daytime and general low-temperature environments despite having an infrared detector to use an InfraRed Emitting Diode (IrED) to photograph a subject in a low light environment such as at night and indoors. It provides a camera module and a portable terminal including the same. In particular, the two-band filter provided in the camera module transmits visible light in a general illumination environment and transmits infrared light in a specific wavelength band so that a subject can be photographed in a low illumination environment. Therefore, in low-light environment, the subject can be photographed using infrared light. In general light environment, color reproducibility can be maintained by transmitting only visible light and a portion of infrared light in a specific wavelength range.

Low light environment, general light environment, infrared light emitting diode part, 2-band filter, white light phenomenon

Description

CAMERA MODULE AND PORTABLE TERMINAL HAVING THE SAME}

The present invention relates to a camera module and a portable terminal having the same, and more particularly, to photograph using an infrared light emitting diode in a night and low light environment, and to transmit only visible light and infrared light in a specific wavelength range in daytime and general environment. The present invention relates to a camera photographing module for maintaining color reproducibility using a band filter and a portable terminal for video telephony having the same.

In recent years, with the rapid development of semiconductor technology, as electronic devices become more compact, complex electronic devices, in which existing independent devices are integrated into one electronic device, have appeared. Representative composite electronic devices include mobile phones having a camera module in which a mobile phone and a camera are combined.

In other words, the initial mobile phone was designed to make only a voice call, but as the popularity of mobile phones has increased rapidly, the manufacturing technology and communication technology of mobile phones have dramatically developed. As a result, mobile phones support multiple chord ringtones or color displays, and various functions such as playing games, searching the Internet, receiving and sending e-mails, and paying bills are becoming common. In addition, a so-called camera phone that has an optical camera attached to a mobile phone has been developed to take a picture of a subject and wirelessly transmit and receive a captured image. It is gone. In particular, recently, a video call phone capable of making a video call using a camera has been developed and used.

The camera included in the mobile phone is substantially composed of a CMOS Image Sensor (CIS) camera module composed of an image pickup device coupled with a lens module. The camera module includes a condenser lens, an infrared filter, an image sensor, and a barrel or a housing. . The condenser lens collects light incident from a subject on an image sensor, and the infrared filter is provided on an upper surface of the condenser lens to block infrared components included in the incident light. The image sensor includes a CMOS or CCD image sensor, and an image of the subject is formed by the condenser lens. The housing aligns the condenser lens, infrared filter and image sensor on the same optical axis.

On the other hand, the CIS camera used in the composite device has a disadvantage in that the shooting freely in bright lighting, but difficult to shoot in a place or night without lighting.

Recently, an infrared light emitting diode is applied to a CIS camera used in the composite device, so that photography can be performed even in a low light environment. Therefore, the CIS camera to which the infrared light emitting diode is applied does not include an infrared filter to transmit infrared components from the infrared light emitting diode.

However, when shooting and making video calls in daytime and general environments, infrared light passes through the infrared filter as it is. That is, in the daytime and the general environment, since visible light and infrared light transmitted through the infrared filter are incident on the lens and the sensor of the CIS camera, the color reproducibility of the image is inferior.

The present invention has been made in view of the above problems, and the present invention is applied to an infrared light emitting diode (InfraRed Emitting Diode: IRED) that emits infrared light to a camera module having a two-band filter for transmitting visible and infrared light in a specific wavelength range. It is to provide a camera module capable of night viewing and night photographing.

Camera module according to an embodiment of the present invention is provided in a portable terminal that performs a complex function such as a shooting function, video recording and playback function, video call function, the camera module is an infrared light emitting diode (IrED) unit, It includes a camera unit, a control unit and a transmission unit. The infrared light emitting diode unit emits infrared light having a directivity angle θ of 16 degrees to 28 degrees in order to provide an illuminance environment having a predetermined brightness or more around the subject in the low illuminance environment. The camera unit transmits infrared light having a specific wavelength band of infrared light from the infrared light emitting diode unit to photograph a subject in the low light environment, and a two-band transmitting visible light and infrared light of the specific wavelength band in a general illumination environment. It is provided with a filter. The camera unit photographs a subject based on infrared light or visible light reflected from the subject and converts the subject into an electrical signal. The controller transmits an electrical signal output from the camera unit to an external composite device, and controls the camera unit and the infrared light emitting diode unit according to a control signal input from the composite device. The transmitter transmits and receives an electrical signal between the camera unit, the infrared light emitting diode unit, and the controller.

In embodiments of the present invention, the infrared light emitting diode unit is formed to be spaced apart from the camera unit by 12 mm or more in order to remove the white neck phenomenon that occurs during photographing. In particular, the infrared light emitting diode unit may be formed to be spaced apart from the camera unit by 12 mm to 36 mm.

In addition, in order to provide a predetermined brightness so that a subject photographed in a low light environment can be identified and to maintain color reproducibility of a subject photographed in a general light environment, the two-band filter is configured to transmit visible light and infrared light in a specific wavelength range. Can be designed.

In embodiments of the present invention, the two-band filter is disposed between the condenser lens and the image sensor to transmit infrared light having a wavelength band of 890nm to 1000nm. Further, the two-band filter transmits visible light having a wavelength band of 400 nm to 650 nm in addition to infrared light having the wavelength band.

In embodiments of the present invention, the two-band filter is designed to maximize the amount of infrared light transmitted in the low light environment relative to the amount of infrared light transmitted in the general light environment. In this case, the amount of infrared light transmitted in the low light environment is determined by the product of the spectral characteristics of the infrared light emitting diode unit, the transmittance of the two-band filter and the spectral characteristics of the image sensor. And when the range of the spectral characteristics of the infrared light emitting diode portion and the spectral characteristics of the image sensor is fixed, the transmittance of the two-band filter within 30% to 70% to maximize the amount of infrared light transmitted in the low light environment Adjusted in

In order to achieve the above object of the present invention, the portable terminal according to the embodiments of the present invention is integrated with a camera module having the above-described features and devices having different functions.

Camera module having a two-band filter and a portable terminal having the same according to the present invention as described above has the following advantages.

First, the CIS camera used in the composite device detects illuminance from incident light and photographs a subject by operating an infrared light emitting diode in a place where there is no bright light as well as a place where there is no light or at night.

Second, the two-band filter selectively transmits only infrared light having a wavelength range of 890 nm to 1000 nm with relatively low sensing sensitivity, thereby maintaining color reproducibility even in a general illumination environment such as daytime.

Third, since the infrared light emitting diode unit and the camera unit are disposed at a predetermined distance apart from each other, the white light phenomenon generated in the captured image may be removed to achieve more clear image quality at night.

Fourth, the infrared light emitting diode unit emits infrared light having a directivity angle (θ) of 16 to 28 degrees, thereby preventing the central saturation phenomenon that the infrared light is concentrated in the center of the subject, it is possible to implement a clear image quality as a whole.

Hereinafter, a camera module and a portable terminal having the same according to embodiments of the present invention will be described in detail with reference to the accompanying drawings. As the inventive concept allows for various changes and numerous modifications, particular embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. Like reference numerals are used for like elements in describing each drawing. In the accompanying drawings, the dimensions of the structure is shown to be larger than the actual size for clarity of the invention, or to reduce the actual size to understand the schematic configuration.

In addition, terms such as first and second may be used to describe various components, but the components should not be limited by the 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 the second component, and similarly, the second component may also be referred to as the first component. On the other hand, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

1 is a view for explaining a camera module according to an embodiment of the present invention, Figure 2 is a block diagram for explaining in detail the structure of the camera shown in FIG.

Referring to FIG. 1, a camera module according to an exemplary embodiment of the present invention includes a camera unit 100, an infrared light emitting diode (IRED) unit 200, a transmitter 300, and a controller 400.

Referring to FIG. 2, the camera unit 100 is mounted in one region on the substrate 150. At this time, the camera unit 100 and the substrate 150 are electrically coupled to each other by the bonding wire 140. For example, the substrate 150 may include a printed circuit board (PCB), a flexible circuit board (FPCB), a ceramic substrate, and the like.

The camera unit 100 photographs a subject based on the input infrared light or visible light and converts it into an electric signal. For example, the camera unit 100 converts an image signal from the subject into an electrical signal. Accordingly, the camera unit 100 includes a condenser lens 110, an image sensor 120, a housing 130, and a two-band filter 160.

The condenser lens 110 condenses an image incident from the subject, that is, light for representing the image, to the image sensor 120. The condenser lens 110 is disposed in front of the camera unit 100 in a direction toward the subject to focus the image signal representing the image of the subject to the image sensor 120. For example, the condenser lens 110 may be a convex lens.

The image sensor 120 is disposed to form an image of a subject collected by the condenser lens 110. That is, the image sensor 120 is disposed at the rear end of the condenser lens 110 based on the subject, and the light collected from the condenser lens 110 is formed on the image sensor 120.

In the embodiments of the present invention, the condenser lens 110 and the image sensor 120 are spaced apart by a predetermined distance. The spaced distance may be adjusted to correspond to the focal length of the condensing lens 110. The separation distance may be controlled through a switch (not shown) disposed separately in the outside. For example, the distance between the condenser lens 110 and the image sensor 120 may be adjusted to correspond to the infrared light shooting at night and the visible light shooting at the daytime shooting, respectively. Accordingly, by controlling the focal length according to the infrared light and the visible light, a clearer picture quality may be realized. In this case, in order to precisely adjust the separation distance between the condenser lens 110 and the image sensor 120, a servo motor or the like may be used. On the other hand, clear image quality can also be achieved through software image quality correction rather than mechanical distance control.

The image sensor 120 senses visible light and infrared light having a specific wavelength band. For example, the image sensor 120 may include a charge coupled device (CCD) image sensor, a complementary metal oxide image sensor, or the like. When the image sensor 120 is a CD image sensor, the image sensor 120 may sense an image of the subject by flowing a current corresponding to the focused light. The image sensor 120 may have various sensing sensitivity depending on the wavelength band of the focused light. For example, the image sensor 120 may have a different sensitivity to infrared light having a wavelength band around 800 nm and a sensitivity to infrared light having a wavelength band around 900 nm. In the embodiments of the present invention, the image sensor 120 has a low sensitivity to infrared light having a relatively large wavelength band.

In example embodiments, the image sensor 120 may convert incident light into an electrical signal.

The housing 130 or the barrel is disposed to protect the condenser lens 110 and the image sensor 120 from external shocks. In addition, the housing 130 integrates the condenser lens 110 and the image sensor 120 into an integrated camera unit 100 arranged to be spaced apart from each other by a predetermined interval. In an embodiment of the invention, the housing 130 aligns the condenser lens 110 and the image sensor 120 on the same optical axis. That is, the housing 130 arranges the condenser lens 110 and the image sensor 120 such that the subject, the condenser lens 110 and the image sensor 120 are aligned on the same optical axis.

In the embodiments of the present invention, the two-band filter 160 transmits only light of a specific wavelength band among the light passing through the condenser lens 110. In this case, the two-band filter 160 is a filter that transmits infrared light and visible light in a specific wavelength band, respectively, and is defined as two-band to explain the number according to the type of light. Therefore, this is not an expression for specifying the number of wavelength bands transmitted, and is not limited to the number. Therefore, the scope of the present invention is not limited to the two-band filter 160.

In the embodiment of the present invention, the two-band filter 160 transmits only infrared light having a wavelength band of 890 nm to 1000 nm of the infrared light emitted from the infrared light emitting diode unit 200. In addition, the two-band filter 160 transmits visible light having a wavelength band of 400nm to 650nm.

In other embodiments of the present invention, the two-band filter 160 that transmits both visible light and infrared light in a specific wavelength range is a dual mode filter (not shown) that selectively transmits visible light and infrared light in a specific wavelength range. Can be replaced with

The dual mode filter is designed to transmit infrared light in a specific wavelength band in a low light environment and to transmit visible light in a general light environment. For example, the dual mode filter transmits infrared light having a wavelength range of 890 nm to 1000 nm among the infrared light emitted from the infrared light emitting diode unit 200 to photograph the subject in a low light environment, and in a general light environment Blocks external light and transmits visible light having a wavelength band of 400 nm to 650 nm.

Meanwhile, in order for the dual mode filter to transmit light having a different wavelength band according to an external illuminance environment, the camera unit 100 senses an external illuminance and transmits the sensed external illuminance value to the controller 400. It may further include a sensor unit (not shown).

At this time, the controller 400 determines the external illuminance environment by comparing the external illuminance value received from the illuminance sensor unit with a set reference illuminance value. That is, when the measured external illuminance value is equal to or less than the reference illuminance value, the controller 400 may determine the external illuminance environment as the low illuminance environment.

The controller 400 transmits a mode selection signal to the dual mode filter according to the external illumination environment. Here, the mode selection signal is a signal for selecting a specific mode from a low light environment and a normal mode environment.

Therefore, the dual mode filter transmits visible light having a wavelength range of 400 nm to 650 nm in a general illuminance environment and infrared light having a wavelength range of 890 nm to 1000 nm in a low illuminance environment according to a mode selection signal from the controller 400.

As described above, effects of the two-band filter 160 or the dual mode filter transmitted through the light of a specific wavelength band will be described in detail with reference to the sensing sensitivity and color reproducibility of the image sensor 120 which will be described later.

The infrared light emitting diode unit 200 is spaced apart from the camera unit 100 by a predetermined distance and mounted in one region on the substrate 150. That is, the camera unit 100 and the infrared light emitting diode unit 200 are spaced apart from one another on the substrate 150. In the embodiment of the present invention, the infrared light emitting diode unit 200 is disposed to be spaced apart from the camera unit 100 by 12 mm to 36 mm.

In addition, the directivity angle θ of the infrared light emitted from the infrared light emitting diode unit 200 has a set angle. In an embodiment of the present invention, the directivity angle θ of the infrared light emitted from the infrared light emitting diode unit 200 may be 16 degrees to 28 degrees.

The transmitter 300 transmits and receives an electrical signal between the camera unit 100, the infrared light emitting diode unit 200, and the controller 400. For example, the transmitter 300 transmits an electric signal related to the image of the subject sensed by the camera unit 100 to the controller 400. In addition, the transmission unit 300 receives a control signal regarding the operation of the camera unit 100 and the infrared light emitting diode unit 200 from the control unit 400, the camera unit 100 and the infrared light emitting diode unit 200. To send. For example, the transmitter 300 is composed of a flexible printed circuit board (FPCB). In contrast, the transmitter 300 may include various means for transmitting and receiving an electrical signal between the camera unit 100, the infrared light emitting diode unit 200, and the controller 400.

The controller 400 transmits an electrical signal output from the camera unit 100 to an external device such as a mobile phone, and controls the camera unit 100 and the infrared light emitting diode unit 200 according to a control signal input from the external device. To control. On the other hand, the control unit 400 is electrically connected to the camera unit 100 and the infrared light emitting diode unit 200 through the transmission unit 300. For example, the controller 400 may include another area of the substrate 150 adjacent to one region of the substrate 150 on which the camera unit 100 and the infrared light emitting diode unit 200 are disposed and the transmission unit 300 therebetween. May be placed in the area.

As described above, the camera module according to the embodiment of the present invention adjusts the separation distance between the camera unit 100 and the infrared light emitting diode unit 200, and the like, and the infrared light of the wavelength band corresponding to the sensing sensitivity of the image sensor 120. By using this, the photographing quality of the subject can be improved.

3 is a view for explaining the principle of image acquisition of the camera module according to an embodiment of the present invention.

Referring to FIG. 3, when photographing in a low light environment using a camera module of a multi-device such as a mobile phone, the infrared light emitting diode unit 200 emits infrared light to a subject, and the camera unit 100 from the subject. It senses the reflected infrared light and converts it into an electric signal and transmits it to an external composite device. In this way, the camera module can capture an image of the subject.

On the other hand, the camera module provided in the conventional portable terminal is almost parallel to the optical axis of the camera unit 100 and the light axis of the infrared light emitting diode unit 200. Accordingly, when the camera unit 100 and the infrared light emitting diode unit 200 are disposed adjacent to each other, a white-eye phenomenon or a red-eye phenomenon in which the eyes of the photographed subject appear white is generated. In particular, the white-eye phenomenon occurs more frequently according to the miniaturization of portable devices, the simplification of design, and the like. Therefore, in order to prevent the white neck phenomenon, the camera unit 100 and the infrared light emitting diode unit 200 need to be spaced apart by a predetermined distance or more.

On the other hand, since experimental data and photographing pictures for explaining the prevention of white neck phenomenon according to the separation distance between the camera unit 100 and the infrared light emitting diode unit 200 are shown in detail in Figures 4a to 4c, Figures 4a to 4c. This will be described in detail with reference to FIG. 4C.

In addition, the amount of infrared light radiated to the subject may vary according to the directivity angle θ of the infrared light emitted from the infrared light emitting diode unit 200. For example, when the infrared angle θ of the infrared light emitted by the infrared light emitting diode unit 200 is small, infrared light is concentrated at the center of the subject, and thus the photographed subject cannot be identified, and the infrared light emitting diode unit ( When the directivity angle θ of the infrared light emitted by 200 is large, a problem arises in that the amount of light reflected from the subject is insufficient to identify the photographed subject. Therefore, in order to prevent the saturation phenomenon, the infrared light emitting diode unit 200 needs to emit infrared light having a specific direction angle θ.

On the other hand, since experimental data and photographing pictures for explaining the prevention of the central saturation according to the direction angle (θ) of the infrared light emitted by the infrared light emitting diode unit 200 are shown in Figures 5a to 5c, This will be described in detail with reference to FIGS. 5A to 5C.

4A is a photograph of an actual photograph of a subject according to the separation distance between the camera unit and the infrared light emitting diode unit of FIG. 1, and FIG. 4B is a table for describing pupil brightness of the subjects of the photographs according to the separation distance of FIG. 4A. 4C is a graph for explaining the separation distance and pupil brightness of FIG. 4B.

4A to 4C, the separation distance between the camera unit 100 and the infrared light emitting diode unit 200, the directivity angle of the infrared light emitted by the infrared light emitting diode unit 200, and the surrounding environment for photographing a subject The photographing quality of the subject was tested according to the illuminance representing the brightness of.

In this experiment, the separation distance between the camera unit 100 and the infrared light emitting diode unit 200 was set to 8 mm, 10 mm, 12 mm, 20 mm, 28 mm as measured values, and the infrared light emitting diode unit 200 was measured. The directivity angle of the infrared light emitted by is set to 20 degrees. In addition, to express photographing a subject in a night or dark environment, illuminance was set to 0, 5, 10 lux (lux) as the measured value. On the other hand, since 0 to 10㏓ all represent the brightness of a dark environment or an environment photographed at night, the experimental data values for illuminance are substantially no difference. Therefore, the detailed description of the results according to the roughness of the experimental data will be omitted.

In this experiment, in order to determine the occurrence of the white-eye phenomenon, which is a phenomenon in which the subject's eyes appear white, the brightness of black representing the eye color is defined as 7.5 IRE (Institute of Radio Engineers). This is cited by the Institute of Electrical and Electronics Engineers (IEEE), which defines the black level of brightness (luminance) as 7.5 IRE. In this case, the IRE expresses the brightness of a video signal as a percentage of the highest brightness to represent a relationship between video electrical output, brightness, and density by the IEEE. In other words, the IRE unit is a unit representing the amplitude of the TV signal determined by the IRE, and the electric signal 1.0 V corresponds to 140 IRE. That is, it corresponds to 1 IRE = 7.14 kHz. Accordingly, white in the video signal refers to 100 IRE, and black refers to 0 IRE. Here, 0 IRE means a level without the video signal itself (ie, Pedestal Level), so the brightness (luminance) of the actual black level is 7.5 IRE. Therefore, in this experiment, in order to express the brightness of black corresponding to the eye color of the subject, the eye brightness of the photographed subject should be defined as 7.5 IRE or less.

Looking at the occurrence of the white neck phenomenon according to the separation distance between the camera unit 100 and the infrared light emitting diode unit 200 with reference to Figure 4a, the separation distance between the camera unit 100 and the infrared light emitting diode unit 200. When 10 mm or less, it can be seen that the white neck phenomenon occurs in the pictures of the subject. On the contrary, when the separation distance between the camera unit 100 and the infrared light emitting diode unit 200 is 12 mm or more, it can be seen that the white neck phenomenon does not occur. Therefore, according to the experimental data, it can be said that there is a critical significance before and after the separation distance between the camera unit 100 and the infrared light emitting diode unit 200 is 12mm. Of course, the same result can be obtained when the photographs of the subjects are visually observed.

Referring to FIGS. 4B and 4C, the brightness of the eyes of the subject was measured to examine the occurrence of white eye phenomenon in the photographed picture according to the separation distance between the camera unit 100 and the infrared light emitting diode unit 200. As mentioned above, when the pupil brightness of the subject is 7.5 IRE or less, it can be seen that black is expressed. Thus, when the separation distance between the camera unit 100 and the infrared light emitting diode unit 200 is 10 mm, it can be seen that the pupil brightness of the subject is 26, 28, 32 IRE. In addition, even when the separation distance between the camera unit 100 and the infrared light emitting diode unit 200 is 11 mm, it can be seen that the pupil brightness of the subject is 10 IRE or more. On the contrary, when the separation distance between the camera unit 100 and the infrared light emitting diode unit 200 is 12 mm, it can be seen that they are 7.2, 6.8, and 5.6 IRE. That is, when the separation distance is 12mm, it can be seen that the pupil brightness of the subject expresses black defined by the IEEE. Furthermore, when the separation distance between the camera unit 100 and the infrared light emitting diode unit 200 is 12 mm or more, it can be seen that the eye brightness of the subject expresses black more clearly. Therefore, according to the experimental data, it can be said that the distance between the camera unit 100 and the infrared light emitting diode unit 200 is 12 mm before and after the critical significance. Furthermore, when the separation distance between the camera unit 100 and the infrared light emitting diode unit 200 is 12 mm or more, the brightness when the separation distance is 12 mm for not only the brightness of the eyes of the subject but also the brightness of the subject and the surrounding environment. In contrast, the separation distance within 15% of the change in brightness corresponds to 36 mm. Accordingly, when the separation distance between the camera unit 100 and the infrared light emitting diode unit 200 is 12 mm to 36 mm, the white eye phenomenon may be removed and the photographing quality may be maintained.

As such, when the separation distance between the camera unit 100 and the infrared light emitting diode unit 200 is 12 mm or more, the white neck phenomenon may be removed from the photographed subject.

5A is a photograph of an actual photograph of a subject according to a directivity angle of infrared light emitted from the infrared light emitting diode unit of FIG. 1, and FIG. 5B is a table for describing brightness of photographs according to the directivity angle of FIG. 5A. 5C is a graph for explaining the orientation angle of FIG. 5B and the brightness of photographs.

5A to 5C, in the exemplary embodiment of the present invention, the subject is photographed according to the center brightness and the ambient brightness of the pictures taken according to the directivity of the infrared light emitted by the infrared light emitting diode unit 200. The quality was tested.

In the present experiment, since the infrared light emitting diode unit 200 emits infrared light having a wavelength range of 890 nm to 1000 nm, or the two-band filter 160 transmits infrared light having a wavelength range of 890 nm to 1000 nm. In this experiment, 940 nm was set as a reference value, and the distance between the camera unit 100 and the infrared light emitting diode unit 200 was set to 12 mm. The reason is that the smaller the separation distance, the higher the sensing sensitivity of the brightness of the photographed picture, and 12mm, the minimum separation distance of 12mm to 36mm according to an embodiment of the present invention is set as a reference value Experiment. And the directivity angle of infrared light set 4, 11.5, 12, 20, 28, 35 degree | times as a measured value.

In this experiment, the center brightness is defined as 50 IRE or more and the ambient brightness is defined as 25 IRE or more. This is based on the definition of the appropriate brightness of 50 IRE or more, based on the maximum brightness of 100 IRE, based on the analog video signal low light sensitivity characteristic of the IEEE. In addition, the peripheral brightness is defined as 25 IRE or more because the subject can be expressed only when it is 25 IRE or more, which is half of the central brightness of the subject 50 IRE.

Referring to FIGS. 5A and 5B, when looking at the center brightness and the ambient brightness of the photographed photograph at the directivity angle of infrared light, when the directivity angles are 4 degrees and 11.5 degrees, the center brightness is measured at 100 IRE and 96 IRE and the ambient brightness is It was measured from 7 IRE to 11 IRE. That is, when the directivity angles are 4 degrees and 11.5 degrees, the photographing of the subject may be confirmed that the quality of photographing is degraded to the extent that it is difficult to identify the subject due to the central saturation of brightness. In addition, when the orientation angle was 35 degrees, the central brightness was measured at 16 IRE and the ambient brightness was measured at 6 IRE to 10 IRE. Therefore, when the orientation angle is 35 degrees, it can be confirmed that the photographing of the subject is dark so that the photographing quality is deteriorated so that it is difficult to identify the subject.

In contrast, when the orientation angle was 16 degrees to 28 degrees, the central brightness was measured at 56 IRE to 69 IRE and the ambient brightness was measured at 25 IRE to 30 IRE. Therefore, when the orientation angle is 16 degrees to 28 degrees, not only the central saturation phenomenon but also the overall dark phenomenon does not occur and it is confirmed that the photographing quality is excellent. Of course, the same result can be obtained when the photographs of the subjects are visually observed.

Referring to FIG. 5C, the central saturation phenomenon according to the directivity angle of infrared light is generated. When the directivity angle is 16 degrees to 28 degrees, the center brightness of the subject is measured to be 56 IRE to 69 IRE. Therefore, when the orientation angle is 16 degrees to 28 degrees, it can be seen that the central saturation phenomenon does not occur in the subject. Therefore, it can be said that there is a critical significance before and after the case where the directivity angle of the infrared light emitted from the infrared light emitting diode unit 200 is 16 degrees to 28 degrees.

As such, when the directivity angle of the infrared light from the infrared light emitting diode unit 200 is 16 degrees to 28 degrees, the central brightness and the peripheral brightness of the photographed subject may be represented efficiently. That is, by adjusting the angle of incidence of the infrared light emitted from the infrared light emitting diode unit 200, it is possible to prevent a concentrated saturation phenomenon in which light is concentrated in the center of the subject.

FIG. 6A is a graph illustrating the spectral characteristics of a filter according to the wavelength of incident light, FIG. 6B is a graph illustrating the sensor sensitivity of the image sensor according to the wavelength of infrared light, and FIG. 6C is a graph of the light having R, G, and B components. It is a graph showing the sensor sensitivity of the image sensor according to the wavelength.

In the embodiments of the present invention, the two-band filter 160 transmits only visible light and infrared light in a specific wavelength band. Referring to FIG. 6A, the spectral characteristics of the two-band filter 160 with respect to the input wavelength band have a wavelength band of 890 nm to 1000 nm among visible light having a wavelength band of 400 nm to 650 nm and infrared light components emitted from the infrared light emitting diode unit. It can be seen that only the infrared light is shown. Therefore, the image sensor 120 of the camera unit 100 senses only infrared light having a wavelength band of 890 nm to 1000 nm among the infrared light emitted from the infrared light emitting diode unit 200.

In the embodiments of the present invention, the two-band filter 160 transmits infrared light having a wavelength range of 890 nm to 1000 nm, and at the same time, in the low light environment with respect to the amount of infrared light transmitted in a general illuminance environment. It is designed to maximize the amount of infrared light transmitted. That is, the two-band filter 160 is designed to transmit relatively little infrared light in a low illuminance environment, while transmitting relatively little infrared light in a general illuminance environment.

Herein, the amount of infrared light transmitted in the general illuminance environment is determined within the limit that can satisfy the general camera quality evaluation criteria. In order to satisfy the image quality evaluation criteria, tuning is performed using an image signal processor (ISP) to determine the amount of infrared light in a tunable general illuminance environment. As such, the amount of infrared light transmitted in the general illuminance environment may be determined within a specific range by tuning in advance.

Herein, the amount of infrared light transmitted in the general illuminance environment is determined by multiplying the transmittance of the two-band filter 160 and the spectral characteristics of the image sensor 120. The amount of infrared light transmitted in a low light environment is determined by multiplying the spectral characteristics of the infrared light emitting diode unit 200 by the transmittance of the two-band filter 160 and the spectral characteristics of the image sensor 120.

For example, when the ranges of the spectral characteristics of the infrared light emitting diode unit 200 and the spectral characteristics of the image sensor 120 are fixed, the two-band filter 160 so that the amount of infrared light transmitted in the low light environment is maximized. The transmittance of is controlled within 30% to 70%.

6A is a graph of the optimum filter produced by the method. The filter spectral curves shown can be obtained by computer simulation tools with optimal values including wavelength values of transmission, band width and band maximum transmission.

On the other hand, even when the spectral characteristics of the infrared light emitting diode unit 200 and the spectral characteristics of the image sensor 120 vary depending on the temperature, the infrared light in the general illuminance environment and the infrared light in the low illuminance environment may not be large. have.

On the other hand, when the wavelength of the input image sensor 120 is large, the sensing sensitivity is sharply lowered. 6B and 6C, it can be seen that the sensing sensitivity of the image sensor 120 is significantly lowered when the wavelength band is 890 nm to 1000 nm.

In the general illumination environment, since both visible light and infrared light exist, both visible light and infrared light may be incident on the image sensor 120. The color reproducibility may be degraded in the image of the subject photographed by the transmitted infrared light. For example, when photographing plants, it is difficult to reproduce the green (G) component in an image of plants reflecting a lot of infrared light. Referring to FIG. 6D, it can be seen that color reproducibility is inferior in images of plants having a relatively large amount of green components. In order to solve this problem, it is necessary to minimize the infrared light incident during the daytime shooting.

Accordingly, in order to relatively lower the sensing sensitivity of the image sensor 120, the two-band filter 160 transmits only infrared light having a wavelength band of 890 nm to 1000 nm. Accordingly, the image sensor 120 senses only infrared light having a wavelength band of 890 nm to 1000 nm selectively transmitted by the two-band filter 160. As such, by limiting the wavelength band of the infrared light component sensed by the image sensor 120 to 890 nm to 1000 nm with low sensing sensitivity of the image sensor 120, color reproduction in the daytime is maintained and image quality of the captured image is maintained. Can be improved. Referring to FIG. 6E, when the wavelength range of the infrared light sensed by the image sensor 120 is 890 nm to 1000 nm, an image of plants having a relatively large amount of green components is improved in color reproducibility compared to the image of FIG. 6D. Able to know.

In other embodiments of the present invention, the dual mode filter transmits only visible light when the external illumination environment is a general illumination environment. That is, the dual mode filter transmits only infrared light in a specific wavelength band in a low light environment, and blocks infrared light and transmits visible light in a general light environment.

Therefore, in the general illumination environment, the two-band filter 160 of the camera unit 100 transmits visible light having a wavelength band of 400 nm to 650 nm in addition to infrared light, and the dual mode filter has visible light having a wavelength band of 400 nm to 650 nm. Is selectively transmitted through. Therefore, the image sensor 120 senses visible light having a wavelength band of 400 nm to 650 nm, so that the camera unit 100 including the image sensor 120 can obtain a clear image even with visible light.

In addition, the directivity angle θ of the infrared light emitted from the infrared light emitting diode unit 200 may be 16 to 28 degrees. Here, the direction angle θ refers to the angular range of the total infrared light emitted from the infrared light emitting diode unit 200 on the basis of a line extending from the optical axis of the infrared light emitting diode unit 200. When the luminous intensity of the infrared light emitted from the infrared light emitting diode unit 200 is constant, the optical density of the infrared light emitted may vary according to the magnitude of the directivity angle θ. Therefore, when the direction angle [theta] is small, the intensity of infrared light reaching the specific part of the subject becomes high, and when the direction angle [theta] is large, the intensity of the infrared light which reaches the particular part of the subject becomes small. That is, when the orientation angle θ is small, the center portion of the subject is bright while the peripheral portion may be dark. On the contrary, when the orientation angle θ is large, both the central portion and the peripheral portion of the subject may become dark. Therefore, the infrared light emitting diode unit 200 emits infrared light having a directing angle of 16 degrees to 28 degrees, thereby realizing the brightness of the subject and the surrounding object as the optimum conditions.

Furthermore, in order to prevent infrared light from being incident in a general illuminance environment and degrading color reproducibility, the two-band filter 160 transmits infrared light in a wavelength band having a relatively low sensing sensitivity. In addition, the dual mode filter blocks infrared light in normal light conditions. Accordingly, the image sensor 120 may sense a subject based on incident visible light in a general illumination environment.

In this way, the wavelength band and the directivity angle θ of the infrared light emitted from the infrared light emitting diode unit 200 are specified, and the separation distance between the infrared light emitting diode unit 200 and the camera unit 100 is kept 12 mm or more. In addition, since the two-band filter 160 transmits only light in a specific wavelength band, it is possible to effectively remove white-eye, central saturation, and the like, which may occur during photographing or video communication, and improve color reproducibility.

7 is a diagram illustrating a case where a subject is photographed at night without lighting by using a conventional portable terminal and a portable terminal according to the present invention. That is, FIG. 7 is a diagram for comparing an image photographed at night using a portable terminal 600 having a camera module according to an embodiment of the present invention and an image photographed at night using an existing portable terminal 500. to be.

Referring to FIG. 7, in the case where there is little illumination or at night, the image captured by the conventional portable terminal 500 may be deteriorated such that the image quality is hardly recognized. On the contrary, in the case where there is little illumination or at night, the image photographed by the mobile terminal 600 having the camera module according to the embodiment of the present invention exhibits an image quality that can accurately identify the shape of the subject. It can be seen that. Therefore, when there is little light or at night, when photographing a subject using the portable terminal 600 provided with the camera module according to an embodiment of the present invention, the result of photographs, images, etc. of which the photographing quality is significantly improved is obtained. You can get it.

Meanwhile, although the portable terminal illustrated in FIG. 7 has been described with respect to a mobile phone having a camera module, embodiments of the present invention may be applied to all terminals to which a camera module with an infrared light emitting diode unit is applied.

Accordingly, the portable terminal includes a camera phone, a video call phone, as well as a vehicle, ship, and aviation black box equipped with a camera module. In particular, in the case of the recently used black box is often used in a low light environment, the present invention can be effectively applied.

While the present invention has been described in connection with what is presently considered to be practical and exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

1 is a view for explaining a camera module according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating the structure of the camera unit illustrated in FIG. 1 in detail.

3 is a view for explaining the principle of image acquisition of the camera module according to an embodiment of the present invention.

FIG. 4A illustrates photographs of an actual photograph of a subject according to a separation distance between the camera unit and the infrared light emitting diode unit of FIG. 1.

FIG. 4B is a table for describing pupil brightness of subjects according to the separation distance of FIG. 4A.

4C is a graph for explaining the separation distance and the pupil brightness of FIG. 4B.

FIG. 5A illustrates photographs of an actual photograph of a subject according to a direction angle of infrared light emitted from the infrared light emitting diode unit of FIG. 1.

FIG. 5B is a table for describing brightness of pictures according to the orientation angle of FIG. 5A.

FIG. 5C is a graph for describing the direction angle of FIG. 5B and the brightness of photographs.

6A is a graph for explaining the spectral characteristics of a filter according to the wavelength of incident light.

6B and 6C are graphs illustrating sensor sensitivity of an image sensor according to wavelengths of incident light.

6D and 6E are photographs of actually photographing a subject based on infrared light having different wavelength bands.

7 is a diagram illustrating a case where a subject is photographed at night without lighting by using a conventional portable terminal and a portable terminal according to the present invention.

<Description of the symbols for the main parts of the drawings>

100: CIS camera unit 110: condensing lens

120: image sensor 130: housing

140: bonding wire 150: circuit board

160: two-band filter 200: infrared light emitting diode portion

300: transmission unit 400: control unit

Claims (7)

An infrared light emitting diode (IrED) unit for emitting infrared light having a directivity angle θ of between 16 degrees and 28 degrees to provide an illuminance environment having a predetermined brightness or more around the subject in a low illuminance environment; In order to photograph the subject in the low light environment, the infrared light from the infrared light emitting diode unit transmits infrared light having a specific wavelength band, and a two-band filter for transmitting visible light and infrared light in the specific wavelength band in a general illumination environment. A camera unit for photographing a subject based on infrared light or visible light reflected from the subject and converting the subject into an electrical signal; A control unit which transmits an electrical signal output from the camera unit to an external composite device and controls the camera unit and the infrared light emitting diode unit according to a control signal input from the composite device; And It includes a transmission unit for transmitting and receiving an electrical signal between the camera unit and the infrared light emitting diode unit and the control unit, In order to remove the white neck phenomenon that occurs during shooting, the infrared light emitting diode unit is formed to be spaced apart from the camera unit by 12mm or more, In order to provide a predetermined brightness so that a subject photographed in a low light environment can be distinguished, and to maintain color reproducibility of a subject photographed in a general illuminance environment, the two-band filter is configured for the amount of infrared light transmitted in the general illuminance environment. The camera module, characterized in that designed to maximize the amount of infrared light transmitted in the low light environment. The method of claim 1, And the two-band filter transmits visible light having a wavelength band of 400 nm to 650 nm and infrared light having a wavelength band of 890 nm to 1000 nm among infrared light components emitted from the infrared light emitting diode unit. delete The method of claim 1, The amount of infrared light transmitted in the low light environment is determined by multiplying the spectral characteristics of the infrared light emitting diode portion, the transmittance of the two-band filter, and the spectral characteristics of the image sensor included in the camera portion. . 5. The method of claim 4, When the range of the spectral characteristics of the infrared light emitting diode portion and the spectral characteristics of the image sensor is fixed, the transmittance of the two-band filter within 30% to 70% so that the amount of infrared light transmitted in the low light environment is maximized. Camera module, characterized in that for adjusting. The method of claim 1, The infrared light emitting diode unit is a camera module, characterized in that formed to be spaced apart from the camera by 12mm to 36mm. Portable terminal, characterized in that integrated with the camera module having any one of claims 1, 2 and 4 to 6.

Images