Patent Publication Number: US-2023161140-A1

Title: Contactless type optical device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. application Ser. No. 17/488,645, filed on Sep. 29, 2021, which claims priority to Korean Application No. 10-2021-0064342, filed on May 18, 2021, the content of each of which is hereby incorporated by reference into this application. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a contactless type optical device for acquiring a fingerprint image in a contactless manner. 
     BACKGROUND 
     Generally, a contact type digital optical device (or contact type image acquisition device) uses a method of correcting an image based on a PPI (Pixels per inch) of a subject&#39;s image obtained from a contact surface so as to achieve the PPI of a uniform image. 
     However, since a contactless type optical device (or contactless type image acquisition device) is configured such that a subject to be photographed is not fixed, the PPI of a photographed image is changed depending on a distance (or photographing distance) between the subject and the contactless type optical device. Further, the contactless type optical device undergoes a change in shade of the acquired subject&#39;s image depending on the position of an illumination. 
     Therefore, there is a need for a contactless type optical device (or contactless type image acquisition device) that has little change in shade of the subject&#39;s image while acquiring the image of the subject having a uniform PPI regardless of a distance from the subject. 
     SUMMARY 
     In view of the above, the present disclosure provides a contactless type optical device capable of acquiring a fingerprint image in a contactless manner. 
     Further, the present disclosure provides a contactless type optical device that has little change in shade of a subject&#39;s image while acquiring the subject&#39;s image having a uniform PPI regardless of a distance from the subject. 
     However, the present disclosure is not limited to the above-described objectives, and those skilled in the art can clearly understand other objectives from the following description. In accordance with a first embodiment of the present disclosure, there is provided a contactless type optical device including: an image photographing module configured to photograph a subject, the image photographing module including a photographing lens forming an image of light that is scattered from the subject and is incident on the photographing lens; an illuminator configured to radiate illumination light, the illuminator being disposed within a predetermined distance from the image photographing module; a first lens configured to reduce an incidence angle of the illumination light traveling from the illuminator; and a second lens having a first surface to which the illumination light passing through the first lens is incident to be transmitted, and a second surface to which the subject&#39;s scattered light scattered from the subject is incident to be transmitted, wherein the photographing lens is disposed such that the subject&#39;s scattered light passing through the second lens is incident. 
     The contactless type optical device may further include a reflector to reflect the subject&#39;s scattered light so that the subject&#39;s scattered light is incident on the image photographing module, wherein the first lens is disposed to be spaced apart from the illuminator to face the illuminator. 
     The reflector may include a first reflector and a second reflector disposed at respective preset angles between the image photographing module and the second lens to reflect the subject&#39;s scattered light, and the first reflector and the second reflector may be disposed to be spaced apart from each other by a predetermined distance to face each other. 
     The illuminator, the reflector, and the second lens may be configured such that the illumination light is incident towards the second lens without being reflected by the reflector. 
     The second lens may be configured such that the subject&#39;s scattered light scattered from the subject is incident on the image photographing module at a view angle ranging from −50 to 5°. 
     The first lens may include a convex lens. 
     The second lens may be formed of an objective lens that is a convex lens. 
     An optical axis of the illuminator may be disposed between the first reflector and the second reflector. 
     In accordance with a second embodiment of the present disclosure, there is provided a contactless type optical device including: an image photographing module configured to photograph a subject, the image photographing module including a photographing lens forming an image of light that is scattered from the subject and is incident on the photographing lens; an illuminator configured to radiate illumination light, the illuminator being disposed within a predetermined distance from the image photographing module; a first lens configured to reduce an incidence angle of the illumination light traveling from the illuminator; and a glass plate having a first surface to which the illumination light passing through the first lens is incident to be transmitted, and a second surface to which the subject&#39;s scattered light scattered from the subject is incident to be transmitted, wherein the photographing lens is disposed such that the subject&#39;s scattered light passing through the glass plate is incident on the photographing lens. 
     The contactless type optical device may further include a reflector to reflect the subject&#39;s scattered light so that the subject&#39;s scattered light is incident on the image photographing module. The first lens may be disposed to be spaced apart from the illuminator to face the illuminator. 
     The reflector may include a first reflector and a second reflector disposed at respective preset angles between the image photographing module and the glass plate to reflect the subject&#39;s scattered light, and the first reflector and the second reflector may be disposed to be spaced apart from each other by a predetermined distance to face each other. 
     At least one of the first reflector and the second reflector may include a concave mirror. 
     The illuminator, the reflector, and the glass plate may be configured such that the illumination light is incident towards the glass plate without being reflected by the reflector. 
     The glass plate may be configured such that the subject&#39;s scattered light scattered from the subject is incident on the image photographing module at a view angle ranging from −5° to 5°. 
     The first lens may include a convex lens. 
     An optical axis of the illuminator may be disposed between the first reflector and the second reflector. 
     A contactless type optical device according to an embodiment of the present disclosure is configured such that a subject&#39;s scattered light scattered from a subject located at a focal distance of a light transmitter (second lens or glass plate) located at a focal distance of a photographing lens of an image photographing module is incident on a light transmitter to be transmitted and then the transmitted subject&#39;s scattered light is incident on the image photographing module, so that it is possible to acquire a subject&#39;s image having a uniform PPI (Pixels per inch) regardless of a distance between the image photographing module and the subject. 
     Since the subject&#39;s scattered light scattered from the subject is reflected by a reflector and is incident on the image photographing module, a volume required for the light scattered from the subject to be incident on the image photographing module is reduced as compared to a case where the subject&#39;s scattered light scattered from the subject is linearly incident on the image photographing module, and thereby the size of a product can be reduced. 
     Further, a contactless type optical device according to an embodiment of the present disclosure is configured such that, while illumination light radiated by an illuminator is transmitted to a first lens and a second lens, the incidence angle of the transmitted light is reduced and the density of the light is increased, so that the image photographing module can acquire a subject&#39;s image in which an outline of a subject is clear and a change in shade is little. 
     However, the present disclosure is not limited to the above-described effects, and those skilled in the art can clearly understand other effects from the following description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a diagram illustrating a change in PPI of a subject&#39;s image acquired depending on a distance between a subject and an image photographing module. 
         FIG.  2    is a diagram illustrating the acquisition of a subject&#39;s image having a uniform PPI regardless of a distance between a subject and an image photographing module using an objective lens that is a convex lens. 
         FIG.  3    is a diagram illustrating a subject&#39;s image acquired by an image photographing module when a subject and an illumination are at a short distance. 
         FIG.  4    is a diagram illustrating a subject&#39;s image acquired by the image photographing module when a subject and an illumination are at a long distance. 
         FIG.  5    is a diagram illustrating the configuration of a contactless type optical device in accordance with an embodiment of the present disclosure. 
         FIG.  6    is a diagram illustrating a focal distance of a photographing lens in the contactless type optical device in accordance with the embodiment of the present disclosure. 
         FIG.  7    is a diagram illustrating a focal distance of a photographing lens of an image photographing module in the contactless type optical device in accordance with the embodiment of the present disclosure. 
         FIG.  8    is a diagram illustrating a path of light passing through a first lens in the contactless type optical device in accordance with the embodiment of the present disclosure. 
         FIG.  9    is a diagram illustrating the configuration of a contactless type optical device in accordance with another embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, specific embodiments for implementing a spirit of the present disclosure will be described in detail with reference to the drawings. 
     In describing the present disclosure, detailed descriptions of known configurations or functions may be omitted to clarify the present disclosure. 
     When an element is referred to as being ‘connected’ to, ‘supported’ by, ‘accessed’ to, ‘supplied’ to, ‘transferred’ to, or ‘contacted’ with another element, it should be understood that the element may be directly connected to, supported by, accessed to, supplied to, transferred to, or contacted with another element, but that other elements may exist in the middle. 
     The terms used in the present disclosure are only used for describing specific embodiments, and are not intended to limit the present disclosure. Singular expressions include plural expressions unless the context clearly indicates otherwise. 
     Further, in the present disclosure, it is to be noted that expressions, such as the upper side and the lower side, are described based on the illustration of drawings, but may be modified if directions of corresponding objects are changed. For the same reasons, some components are exaggerated, omitted, or schematically illustrated in the accompanying drawings, and the size of each component does not fully reflect the actual size. 
     Terms including ordinal numbers, such as first and second, may be used for describing various elements, but the corresponding elements are not limited by these terms. These terms are only used for the purpose of distinguishing one element from another element. 
     In the present specification, it is to be understood that the terms such as “including” are intended to indicate the existence of the certain features, areas, integers, steps, actions, elements, combinations, and/or groups thereof disclosed in the specification, and are not intended to preclude the possibility that one or more other certain features, areas, integers, steps, actions, elements, combinations, and/or groups thereof may exist or may be added. 
     Before describing a contactless type optical device  1  according to an embodiment of the present disclosure with reference to the accompanying drawings, a subject&#39;s image acquired depending on a distance between an image photographing module and a subject or between an illumination and the subject will be described in brief with reference to  FIGS.  1  to  4   . 
       FIG.  1    is a diagram illustrating a change in PPI of a subject&#39;s image acquired depending on a distance between a subject and an image photographing module, and  FIG.  2    is a diagram illustrating the acquisition of a subject&#39;s image having a uniform PPI regardless of a distance between a subject and an image photographing module using an objective lens that is a convex lens. 
     Referring to  FIG.  1   , when comparing an image B capturing a subject A located at a short distance from the image photographing module  30  through an image photographing module  30  with an image B′ capturing a subject A′ located at a long distance from the image photographing module  30  through the image photographing module  30 , it can be seen that the image B capturing the subject A located at the short distance is larger than the image B′ capturing the subject A′ located at the long distance, and the PPI of the image B capturing the subject A located at the short distance is high. 
     In contrast, it can be seen that the image B′ capturing the subject A′ located at the long distance is smaller than the image B capturing the subject a located at the short distance, and the PPI of the image B′ capturing the subject A′ located at the long distance is low. 
     Referring to  FIG.  2   , when a subject&#39;s image is acquired using an objective lens  10  that is a convex lens spaced apart from the image photographing module  30  by a predetermined distance in a direction opposite to the image photographing module  30 , it is possible to have the uniform PPI of an image and photograph the subject of a uniform size regardless of a distance to the subject. 
     In more detail, when the image photographing module  30  photographs the subject, light passing through the objective lens  10  that is the convex lens spaced apart from the image photographing module  30  by a predetermined distance in a direction opposite to the image photographing module  30  may be transmitted as telecentric parallel light, and the focal distance of the objective lens  10  may be infinite. 
     The telecentric parallel light refers to light in which an exit pupil of radiated light is located at an infinite circle. Specifically, a path of the telecentric parallel light means that light is radiated in a parallel or an approximately parallel form. 
     Since a subject C located at a short distance from the image photographing module  30  is located at the focal distance of the objective lens  10  that is the convex lens, and a subject C′ located at a long distance from the image photographing module  30  is also located at the focal distance of the objective lens  10  that is the convex lens, light scattered from the subject located at the focal distance is incident on the image photographing module  30 , and thereby both an image D capturing the subject C located at the short distance through the image photographing module  30  and an image D′ capturing the subject C′ located at the long distance from the image photographing module  30  may have a uniform PPI. 
       FIG.  3    is a diagram illustrating a subject&#39;s image acquired by the image photographing module  30  when a subject and an illumination are at a short distance, and  FIG.  4    is a diagram illustrating a subject&#39;s image acquired by the image photographing module  30  when a subject and an illumination are at a long distance. 
     Referring to  FIG.  3   , when a subject  13  and an illumination  15  are at the short distance, the image I of the subject  13  acquired by the image photographing module  30  undergoes a large change in shade (or brightness), and an outline of the subject  13  may not be clear. 
     Referring to  FIG.  4   , when the subject  13  and the illumination  15  are at the long distance, the image I′ of the subject  13  acquired by the image photographing module  30  undergoes a small change in shade (or brightness), and an outline of the subject  13  may be clear. 
     When the subject  13  and the illumination  15  are at the long distance, the density of light radiated from the illumination  15  is reduced depending on a distance between the subject  13  and the illumination  15 , so that the image of the subject  13  acquired by the image photographing module  30  may become dark. 
     Comparing an incidence angle θ 1  of the light radiated from the illumination  15  when the subject  13  and the illumination  15  are at the short distance with an incidence angle  62  of the light radiated from the illumination  15  when the subject  13  and the illumination  15  are at the long distance, it can be seen that the incidence angle  82  of the light radiated from the illumination  15  when the subject  13  and the illumination  15  are at the long distance is smaller than the incidence angle θ 1  of the light radiated from the illumination  15  when the subject  13  and the illumination  15  are at the short distance. 
     The smaller the incidence angle of the light is, the clearer the subject&#39;s outline in the subject&#39;s image acquired by the image photographing module  30  may be. However, when a distance between the subject  13  and the illumination  15  increases to reduce the incidence angle, the density of light reaching the subject  13  from the illumination  15  is reduced, so that the acquired image of the subject  13  may become dark. 
       FIG.  5    is a diagram illustrating the configuration of a contactless type optical device in accordance with the embodiment of the present disclosure, and  FIG.  6    is a diagram illustrating a focal distance of a photographing lens in the contactless type optical device in accordance with the embodiment of the present disclosure. 
     The contactless type optical device  1  in accordance with the embodiment of the present disclosure may acquire a fingerprint image in a contactless manner. Referring to  FIG.  5   , the contactless type optical device  1  in accordance with the embodiment of the present disclosure may include an image photographing module  100 , an illuminator  200 , a first lens  300 , a second lens  400 , and a reflector  500 . 
     The image photographing module  100  may photograph a subject  3 . The subject  3  may include a user&#39;s finger, and the image photographing module  100  may be a camera that photographs the fingerprint of the user&#39;s finger. The image photographing module  100  may include a photographing lens  110  and an image information generator  120 . 
     The photographing lens  110  may form an image of light that is scattered from the subject  3  and then is incident. 
     The image information generator  120  may convert the formed light image into an electrical signal, and then may generate image information about the subject based on the electrical signal. 
     The illuminator  200  may be disposed within a predetermined distance from the image photographing module  100 , and may radiate illumination light. The illuminator  200  may radiate the illumination light onto a photographing area  50  for the subject  3  that will be described later. 
     The illuminator  200  may be disposed within a predetermined distance from the image photographing module  100  in a horizontal axis to prevent the formation of a light spot due to the illumination light radiated from the illuminator  200  in addition to the subject&#39;s scattered light that is scattered from the subject  3  and is incident on the photographing lens  110 . 
     The first lens  300  may reduce the incidence angle of the illumination light traveling from the illuminator  200 . The first lens  300  may be inclined at a predetermined angle (e.g., 20° to 45°) with respect to the orientation of the second lens  400 , and may be disposed to be deflected from the illuminator  200  and face the second lens  400 . The first lens  300  may be disposed between the illuminator  200  and the second lens  400  that will be described later. The incidence angle of the illumination light radiated from the illuminator  200  may be reduced according to the arrangement of the first lens  300 . The first lens  300  may include a convex lens. 
     The first lens  300  may be configured such that the incidence angle of the illumination light passing through the first lens  300  forms an angle ranging from 20° to 60°. 
     The second lens  400  may be configured such that illumination light radiated from the illuminator  200  is incident on the first lens  300 , illumination light passing through the first lens  300  is incident on and transmitted to a first surface of the second lens  400 , and the subject&#39;s scattered light scattered from the subject  3  is incident on and transmitted to a second surface of the second lens  400 . The first surface on which illumination light passing through the first lens  300  is incident may be a surface facing the first lens  300 , and the second surface on which the subject&#39;s scattered light scattered from the subject  3  is incident may be a surface facing to the subject  3 . The second lens  400  may be formed of the objective lens that is the convex lens. 
     The photographing lens  110  may be disposed such that the subject&#39;s scattered light passing through the second lens  400  is incident. 
     The light passing through the second lens  400  may travel in parallel and telecentrically. In this regard, the expression “light travels telecentrically and in parallel” means that the path of light is in a parallel or approximately parallel form. The incidence angle of the parallel light passing through the second lens  400  may be formed at an angle ranging from −10° to 10° from the second lens  400  such that light travels telecentrically and in parallel. The light passing through the second lens  400  may be transmitted in the form of telecentric and parallel light, so that the focal distance of the second lens  400  may be infinite. 
     Therefore, since the focal distance of the second lens  400  is increased, the subject&#39;s scattered light scattered from the subject  3  located at the focal distance of the second lens  300  is incident on the image photographing module  100 , so that the contactless type optical device  1  may acquire image information of the subject having a uniform PPI regardless of a distance between the image photographing module  100  and the subject  3 . 
     The second lens  400  may be disposed between the photographing area  50  of the subject  3  and the image photographing module  100 . The photographing area  50  of the subject  3  may be an area facing the second surface of the second lens  400  through which light is transmitted from the second lens  400 . The second lens  400  may be configured such that light scattered from the subject  3  is incident on the image photographing module  100  at a view angle ranging from −5° to 5°. 
     Meanwhile, referring to  FIG.  6   , the second lens  300  may be disposed on a focal distance FD of the photographing lens  110  in the image photographing module  100 . 
     The reflector  500  may reflect the subject&#39;s scattered light scattered from the subject  3  so that the subject&#39;s scattered light scattered from the subject  3  is incident on the image photographing module  100 . The reflector  500  may include a plurality of reflectors. The reflector  500  may include a first reflector  510  and a second reflector  520  to reflect the subject&#39;s scattered light scattered from the subject  3 . The first reflector  510  and the second reflector  520  may be spaced apart from each other by a predetermined distance in opposite directions. Each of the first reflector  510  and the second reflector  520  may include a mirror. Further, an optical axis of the illuminator  200  may be disposed between the first reflector  510  and the second reflector  520 . 
     The first reflector  510  and the second reflector  520  may reflect the subject&#39;s scattered light scattered from the subject  3 . 
     In the contactless type optical device  1  according to the embodiment of the present disclosure, the subject&#39;s scattered light scattered from the subject  3  is reflected by the first reflector  510  and the second reflector  520  and then is incident on the image photographing module  100 , so that a volume required for the light scattered from the subject  3  to be incident on the image photographing module  100  is reduced as compared to a case where the subject&#39;s scattered light scattered from the subject  3  is linearly incident on the image photographing module  100 . Consequently, the size of a product (contactless type optical device) can be reduced. 
       FIG.  7    is a diagram illustrating the focal distance of the photographing lens of the image photographing module in the contactless type optical device in accordance with the embodiment of the present disclosure. 
     Referring to  FIG.  7   , it can be seen that the light scattered from the subject  3  is reflected by the first reflector  510  and the second reflector  520  to be incident on the photographing lens  110 . 
     The second lens  400  may be configured such that the subject&#39;s scattered light  420  scattered from the subject  3  is incident on the image photographing module  100  at a view angle ranging from −5° to 5°. 
       FIG.  8    is a diagram illustrating the path of light passing through the first lens  300  in the contactless type optical device in accordance with the embodiment of the present disclosure. 
     Referring to  FIG.  8   , assuming that there is no first lens  300 , illumination light BP radiated from the illuminator  200  may not be radiated onto the photographing area  50  of the subject  3 , while illumination light radiated from the illuminator  200  may be incident on the first lens  300  and illumination light BP passing through the first lens  300  may be radiated onto the photographing area  50  of the subject  3 . 
     Since the incidence angle of the illumination light passing through the first lens  300  is smaller than the incidence angle of the illumination light radiated from the illuminator  200 , the density of the transmitted illumination light may be increased. 
     The optical device  1  according to the embodiment of the present disclosure may prevent light loss, because it is possible to prevent the dispersion of light bundle BP″ radiated onto the photographing area  50  of the subject  3  while the illumination light radiated from the illuminator  200  is transmitted to the first lens  300  and the illumination light BP″ passing through the first lens  300  is transmitted to the second lens  400 . 
     The illuminator  200 , the reflector  500 , and the second lens  400  may be configured such that illumination light radiated from the illuminator  200  is incident on the second lens  400  without being reflected by the reflector  500 . 
     As the illumination light radiated from the illuminator  200  is transmitted to the first lens  300 , the incidence angle of the illumination light passing through the first lens  300  becomes smaller than the incidence angle of the illumination light radiated from the illuminator  200 . As the illumination light passing through the first lens  300  is transmitted to the second lens  400 , the incidence angle of the light BP″ radiated onto the photographing area  50  of the subject  3  may become smaller than the incidence angle of the illumination light transmitted to the first lens  300 . 
     As the incidence angle of the illumination light BP″ radiated onto the photographing area  50  of the subject  3  becomes smaller than the incidence angle of the illumination light radiated from the illuminator  200 , the image photographing module  100  may acquire the image in which the subject&#39;s outline is clear. 
     In the contactless type optical device  1  according to the embodiment of the present disclosure, while the illumination light radiated from the illuminator  200  passes through the first lens  300  and the second lens  400 , the incidence angle of the transmitted illumination light becomes smaller and the density of light increases, so that the image photographing module  100  may acquire the subject&#39;s image in which the outline of the subject  3  is clear and a change in shade is little. 
       FIG.  9    is a diagram illustrating the configuration of a contactless type optical device in accordance with another embodiment of the present disclosure. 
     Referring to  FIG.  9   , the contactless type optical device  1  in accordance with another embodiment of the present disclosure may include an image photographing module  100 , an illuminator  200 , a first lens  300 , a glass plate  410 , and a reflector  500 . 
     Here, since the image photographing module  100 , the illuminator  200 , and the first lens  300  are the same as those of  FIG.  5   , a detailed description thereof will be omitted. 
     The glass plate  410  may be configured such that illumination light radiated from the illuminator  200  is incident on the first lens  300 , illumination light passing through the first lens  300  is incident on and transmitted to a first surface of the glass plate  410 , and the subject&#39;s scattered light scattered from the subject  3  is incident on and transmitted to a second surface of the glass plate  410 . The first surface of the glass plate  410  on which illumination light passing through the first lens  300  is incident may be a surface facing the first lens  300 , and the second surface of the glass plate  410  on which the subject&#39;s scattered light scattered from the subject  3  is incident may be a surface facing the subject  3 . The glass plate  410  may be disposed on the focal distance of the photographing lens  110 . 
     The photographing lens  110  may be disposed such that the subject&#39;s scattered light scattered from the subject  3  passing through the glass plate  410  is incident. 
     The light passing through the glass plate  410  may travel in parallel and telecentrically. In this regard, the expression “light travels telecentrically and in parallel” means that the path of light is in a parallel or an approximately parallel form. The incidence angle of the parallel light passing through the glass plate  410  may be formed at an angle ranging from −10° to 10° with respect to the glass plate  410  such that light travels telecentrically and in parallel. 
     The glass plate  410  may be disposed between the photographing area  50  of the subject  3  and the image photographing module  100 . The photographing area  50  of the subject  3  may be an area facing a surface through which light is transmitted from the glass plate  410 . The glass plate  410  may be configured such that the subject&#39;s scattered light scattered from the subject  3  is incident on the image photographing module  100  at a view angle ranging from −5° to 5°. 
     The reflector  500  may reflect the subject&#39;s scattered light scattered from the subject  3  so that the subject&#39;s scattered light scattered from the subject  3  is incident on the image photographing module  100 . The reflector  500  may include a plurality of reflectors. The reflector  500  may include a first reflector  510  and a second reflector  520  to reflect the subject&#39;s scattered light scattered from the subject  3 . The first reflector  510  and the second reflector  520  may be spaced apart from each other by a predetermined distance in opposite directions. 
     Further, an optical axis of the illuminator  200  may be disposed between the first reflector  510  and the second reflector  520 . 
     The first reflector  510  and the second reflector  520  may include concave mirrors. The concave mirror may have effects similar to those of an objective lens implemented as a convex lens. 
     The first reflector  510  and the second reflector  520  may reflect the subject&#39;s scattered light scattered from the subject  3 . 
     In the contactless type optical device  1  according to another embodiment of the present disclosure, the subject&#39;s scattered light scattered from the subject  3  is reflected by the first reflector  510  and the second reflector  520  and then is incident on the image photographing module  100 , so that a volume required for the light scattered from the subject  3  to be incident on the image photographing module  100  is reduced as compared to a case where the subject&#39;s scattered light scattered from the subject  3  is linearly incident on the image photographing module  100 . Consequently, the size of a product (contactless type optical device) can be reduced. 
     As described above, a contactless type optical device according to the embodiment of the present disclosure is configured such that subject&#39;s scattered light scattered from a subject located at a focal distance of a light transmitter (second lens or glass plate) located at a focal distance of a photographing lens of an image photographing module is incident on a light transmitter to be transmitted and then the transmitted subject&#39;s scattered light is incident on the image photographing module, so that it is possible to acquire a subject&#39;s image having a uniform PPI (Pixels per inch) regardless of a distance between the image photographing module and the subject. 
     Since the subject&#39;s scattered light scattered from the subject is reflected by the reflector and is incident on the image photographing module, a volume required for the light scattered from the subject to be incident on the image photographing module is reduced as compared to a case where the subject&#39;s scattered light scattered from the subject is linearly incident on the image photographing module, and thereby the size of a product can be reduced. 
     Further, a contactless type optical device according to the embodiment of the present disclosure is configured such that, while illumination light radiated by an illuminator is transmitted to the first lens and the second lens, the incidence angle of the transmitted light is reduced and the density of the light is increased, so that the image photographing module can acquire a subject&#39;s image in which an outline of a subject is clear and a change in shade is little. 
     The examples of the present disclosure have been described above as specific embodiments, but these are only examples, and the present disclosure is not limited thereto, and should be construed as having the widest scope according to the technical spirit disclosed in the present specification. A person skilled in the art may combine/substitute the disclosed embodiments to implement a pattern of a shape that is not disclosed, but it also does not depart from the scope of the present disclosure. In addition, those skilled in the art can easily change or modify the disclosed embodiments based on the present specification, and it is clear that such changes or modifications also belong to the scope of the present disclosure.