KR20200079954A - Optical Image Sensor and Display Device having the same - Google Patents

Abstract

The present invention is to provide an optical image sensor capable of obtaining a sufficiently clear object image even with a low-resolution light receiving element, and a display device having the same. The optical image sensor of the present invention includes: a cover substrate; a light receiving element disposed to face the cover substrate and receiving light reflected from a surface of the cover substrate and a light blocking layer disposed between the cover substrate and the light receiving element and having a plurality of pinholes for passing light reflected from the cover substrate to guide the light receiving element. A first distance from the cover substrate to the light blocking layer may be less than or equal to a second distance from the light blocking layer to the light receiving element.

Description

Optical image sensor and display device having the same

The present invention relates to an optical image sensor, and more particularly, to an optical image sensor integrated display device capable of sensing an image of an object.

With the development of information and communication technology, various applications such as laptop computers, tablet PCs, smart phones, personal digital assistants, automated teller machines, and search guidance systems Information and Communication Based System has been developed. Since these systems usually store personal information related to personal privacy, as well as a lot of data requiring confidentiality such as business information or business confidentiality, there is a need to increase security to protect these data.

To this end, a method for enhancing security by using an image sensor capable of recognizing biometric information of a user has been proposed. For example, an image sensor is known that can enhance security by registering or authenticating a system using a fingerprint of a user's finger. As an image sensor, an optical image sensor is widely known.

However, the optical image sensor of the prior art has a problem in that a clear object image cannot be obtained by mixing light reflected from an object when a distance between an object such as a fingerprint to be read and a light receiving element is far.

The present invention is to solve the problems of the conventional optical image sensor to provide an optical image sensor and a display device having the same to obtain a sufficiently clear object image even with a low-resolution light-receiving element.

The optical image sensor of the present invention for achieving the object comprises a cover substrate; A light receiving element disposed to face the cover substrate and receiving light reflected from a surface of the cover substrate; And a light blocking layer disposed between the cover substrate and the light receiving element and having a plurality of pinholes that pass light reflected from the cover substrate to guide the light receiving element, and from the cover substrate to the light blocking layer. The first distance may be configured to be less than or equal to the second distance from the light blocking layer to the light receiving element.

In the above configuration, the plurality of pinholes are spaced apart at a predetermined distance, and the first and second pinholes adjacent to each other pass through the first frame image and the second pinhole formed by light passing through the first pinhole. The second frame image formed by light may be superimposed.

In addition, the plurality of pinholes may include a first pinhole through which the first reflected light reflected from the first region of the cover substrate passes, and a first pinhole adjacent to the first pinhole and adjacent to the first region of the cover substrate. A third region of the light-receiving device including a second pinhole through which the second reflected light reflected in the second region passes and the first reflected light passing through the first pinhole is received to form a first frame image, and the second The fourth region of the light receiving element where the second reflected light passing through the two pinholes is received to form the second frame image may partially overlap.

In addition, the first frame image and the second frame image may be synthesized after being formed as independent images with a parallax.

The display device of the present invention for achieving the above object is a display panel for displaying data; A cover substrate disposed on a first surface of the display panel; It is disposed on a second surface opposite to the first surface of the display panel, and includes a light receiving element that receives light reflected from the surface of the cover substrate, wherein the display panel includes: a light emitting unit that emits light toward the cover substrate; And a plurality of pinholes disposed between the light emitting unit and the light receiving element, and passing through the light emitted from the light emitting unit and reflected by the cover substrate to guide the light receiving element.

In the above configuration, between the plurality of pinholes and the light receiving element may be formed as a light transmitting region.

Further, the plurality of light emitting units may be self-emission types that emit light by themselves.

In addition, the plurality of pinholes are arranged to be spaced apart at a predetermined distance, and the first and second pinholes adjacent to each other are applied to the first frame image formed by the light passing through the first pinhole and the light passing through the second pinhole. It is possible to overlap the second frame image formed by.

In addition, the plurality of pinholes include a first pinhole through which the first reflected light reflected from the first area of the cover substrate passes, and a second pinhole of the cover substrate adjacent to the first pinhole and adjacent to the first area of the cover substrate. A third region of the light-receiving device including a second pinhole through which the second reflected light reflected from the region passes, and receiving the first reflected light passing through the first pinhole to form a first frame image, and the second The fourth region of the light receiving element where the second reflected light passing through the pinhole is received and the second frame image is formed may partially overlap.

In addition, the first frame image and the second frame image may be synthesized after being formed as independent images with a parallax.

According to the optical image sensor of the present invention and a display device having the same, since a light blocking layer having pinholes can be arranged to maximize light transmittance, an effect of clearly recognizing an image of an object can be obtained.

In addition, since the second distance from the light-shielding layer to the light-receiving element is greater than or equal to the first distance from the cover substrate to the light-shielding layer, the sensing image of the object can be enlarged or equalized, thereby improving the sensing accuracy of the object image. You can get the effect you can do.

In addition, the first frame image generated through the first pinhole and the second frame generated through the second pinhole by varying the turn-on time of the light emitting units generating light passing through the first pinhole and the second pinhole adjacent to each other Since images can be obtained independently and composited to obtain a reproduced image, an effect of increasing the resolution of the reproduced image can be obtained.

1 is a cross-sectional view showing an optical image sensor according to an embodiment of the present invention,
Figure 2 is a cross-sectional view schematically showing the image sensing principle of the optical image sensor according to an embodiment of the present invention,
3 is a cross-sectional view showing a display device including an optical image sensor according to an embodiment of the present invention,
4 is a plan view showing a frame of an optical image formed by light passing through a pinhole of an optical image sensor according to an embodiment of the present invention,
5 is a plan view showing a frame of an optical image formed according to a pattern of a light source applied to an optical image sensor according to an embodiment of the present invention, and FIG. 5A is a plan view showing an example of a case where the light source pattern is a square. 5b is a plan view showing an example where the light source pattern is a square;
6 is a flowchart illustrating a process of generating an image by recognizing an object through an optical image sensor according to an embodiment of the present invention.

Hereinafter, a display device according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings. Throughout the specification, the same reference numerals refer to substantially the same components. In the following description, when it is determined that a detailed description of known functions or configurations related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description is omitted or briefly described.

Hereinafter, an optical image sensor according to an exemplary embodiment of the present invention will be described with reference to FIGS. 1 and 2.

1 is a cross-sectional view showing an optical image sensor according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view schematically showing an image sensing principle of an optical image sensor according to an embodiment of the present invention.

1 and 2, an optical image sensor according to an exemplary embodiment of the present invention includes a cover substrate SUB, a light receiving element RE disposed to face the cover substrate SUB, and a cover substrate SUB and light receiving And a light blocking layer LSL disposed between the elements RE.

The cover substrate SUB is an object existing at the top of the display panel DP positioned closest to the object OB so that the object OB can contact or approach for information input.

The light blocking layer LSL includes a plurality of pinholes PH spaced apart from each other by a predetermined distance. The plurality of pin holes PH is a kind of through hole that transmits light reflected by an object OB that is touched or adjacent to the cover substrate SUB to reach the light receiving element RE. The light-blocking layer LSL may be formed using a material having little reflection without transmitting light. The light-blocking layer LSL is preferably formed using a material that does not transmit light, particularly infrared light, and has less reflection. For example, a metal layer such as chromium (Cr) or chromium oxide (CeOx), or a resin to which carbon or black pigment is added may be used as a material constituting the light-shielding layer LSL.

2, the first and second pinholes PH1 and second pinholes adjacent to each other formed in the light blocking layer LSL are reflected by the object OB positioned on the cover substrate SUB, as illustrated in FIG. 2. After sensing the light passing through (PH2), optical information is transmitted to an image sensing IC (not shown).

In the optical image sensor according to the embodiment of the present invention, the first distance L1 from the cover substrate SUB to the light blocking layer LSL is the second distance L2 from the light blocking layer LSL to the light receiving element RE Less than or equal to

Accordingly, the region R3 on the light-receiving element RE side corresponding to the light passing through the first pinhole PH becomes greater than or equal to the region R1 on the object OB side, and passes through the second pinhole PH2. The area R4 on the light-receiving element RE side corresponding to the light is also greater than or equal to the area R2 on the object OB side. The fact that the regions R3 and R4 on the light-receiving element RE are larger than or equal to the regions R1 and R2 on the object OB side may be increased in accuracy because the sensed image is enlarged or equivalent to the original image. Therefore, the optical image sensor according to the embodiment of the present invention does not need to use an expensive high-precision sensor, so that it is possible to obtain an effect of improving sensing accuracy with cost reduction.

In addition, the light receiving element RE forms the first frame F1 when the light passes through the first pinhole PH1 and the second frame F2 when the light passes through the second pinhole PH2. However, since the first distance L1 is less than or equal to the second distance L2, an overlapping frame FO may occur. The overlapping frame FO can be easily removed by generating the first frame F1 and the second frame F2 images at different timings.

Next, a display device to which an optical image sensor is applied according to an embodiment of the present invention will be described with reference to FIG. 3.

3 is a cross-sectional view showing a display device having an optical image sensor according to an embodiment of the present invention.

Referring to FIG. 1, a display device having an optical image sensor according to an embodiment of the present invention is disposed on a display panel DP and a display surface (ie, a surface on which data is displayed) of the display panel DP, and an adhesive layer It includes a cover substrate (SUB) attached to the display panel (DP) by (AD), a light receiving element (RE) disposed on the back surface opposite to the display surface of the display panel (DP).

The display panel DP includes display elements for displaying data such as text, graphics, still images, and moving images. As the display panel DP, a display panel of an electroluminescent display device using a flexible translucent substrate may be used. The display element of the display panel DP includes a plurality of light emitting units LE, which are respectively disposed in pixel regions arranged in a matrix type to realize the color of the display panel DP. The display panel DP also includes a light blocking layer LSL having a plurality of pinholes PH through which light is transmitted, which is disposed under the plurality of light emitting units LE.

An organic light emitting diode used in an organic electroluminescent display device is preferred as the plurality of light emitting units LE, but the present invention is not limited thereto. For example, any self-emission type light emitting unit capable of emitting light within the display panel may be used.

The light blocking layer LSL blocks light that blocks light from outside the surface of the display panel DP and light emitted from the light emitting unit LE from reaching the light receiving element RE disposed on the back surface of the display panel DP. Is layered. The light blocking layer LSL includes a plurality of pinholes PH spaced apart from each other by a predetermined distance. The plurality of pinholes PH are disposed to avoid an area in which the plurality of light emitting units LE are disposed. The plurality of pinholes PH transmits the reflected light when light emitted from the plurality of light emitting units LE is reflected by the object OB that is touched or touched to the cover substrate SUB, thereby receiving the light receiving element RE It is a kind of through hole that makes it reach. The light-blocking layer LSL may be any material that blocks light from passing through the display panel.

The cover substrate SUB is an object existing at the top of the display panel DP positioned closest to the object so that a specific object can be contacted or approached for information input. Hereinafter, a finger having fingerprint information will be described as an example of an object OB contacting the surface of the cover substrate SUB, but the object is not limited thereto. The object OB may be any of those having irregularities including the bone V and the ridge R. That is, the object OB may be a part of the human body including biometric information such as a fingerprint of a finger having irregularities (ie, bones and ridges).

The light receiving element RE senses the light reflected by the object OB and transmitted through the pinholes PH of the light blocking layer LSL, and then transmits the optical information to the image sensing IC (not shown). The image sensing IC uses an optical information received by the light-receiving element RE, that is, an object using the magnitude of the photocurrent flowing from the light-receiving element RE based on the ridge R and the bone V of the finger OB. Image can be reconstructed.

Next, the principle of sensing the image of the object OB using the optical image sensor integrated display device according to the embodiment of the present invention will be described with reference to FIG. 3. In order to help understanding of the description, the object OB is described using an fingerprint of a finger as an example.

When the display panel DP is operated and the light emitting units LE emit light, and the finger OB contacts the cover substrate SUB on the top of the display panel DP, part of the light emitted from the light emitting unit LE Is reflected by the ridge R of the finger OB. Since the ridge R and the bone V of the finger OB lead to a gentle curved shape, a change occurs in the amount of light reflected according to the position between the ridge R and the bone V. In the embodiment of FIG. 3, although the light emission direction and the reflection direction are shown as one line, light from the light emitting unit LE is emitted toward various points on the surface of the cover substrate SUB, and the fingers OB ) Is reflected by the ridge R.

Referring to Figure 3 will be described in more detail with respect to the traveling direction of the light. The refractive index of the cover substrate SUB has a refractive index similar to that of the finger OB. When the light emitted from the light emitting part LE satisfies the total reflection condition on the upper surface of the cover substrate SUB, most of the light reaching the ridge R of the finger OB is absorbed and reaches the bone V Most of the light is totally reflected and continues to progress along the inside of the cover substrate SUB. However, if the light emitted from the light emitting part LE does not satisfy the total reflection condition in the cover substrate SUB, most of the light reaching the ridge R of the finger OB is refracted and reaches the bone V One light is mostly absorbed. Accordingly, some of the light reaching the ridge R and the bone V of the finger OB is emitted out of the display panel DP through the pinholes PH of the light blocking layer LSL, and the light receiving element RE Is condensed on. As a result, the amount of light reflected by the bone V and the ridge R of the finger OB and collected by the light receiving element RE varies depending on the location of the bone V and the ridge R. Therefore, since the photocurrent having different values flows according to different amounts of light to the light receiving element RE, the image sensing IC (not shown) that receives the optical information from the light receiving element RE is light flowing from the light receiving element RE. It is possible to reconstruct the image of the fingerprint based on the magnitude of the current.

According to the display device having the optical image sensor according to an embodiment of the present invention, the light transmittance of the light can be maximized by disposing the light-shielding layer LSL having pinholes PH inside the display panel DP. The image reflected by the light reflected from the bone V and the ridge R of the object OB on the substrate SUB has a different size according to the position between the bone V and the ridge R. The effect can be clearly recognized.

In addition, since the first distance L1 from the cover substrate SUB to the light blocking layer LSL is less than or equal to the second distance L2 from the light blocking layer LSL to the light receiving element RE, the light receiving element ( RE) The light receiving area on the side is greater than or equal to the light reflection area of the object layer, so the object (e.g., finger) (OB) image remains intact (when L1 and L2 are the same) or enlarged (when L2 is greater than L1). You can get the effect you can.

Next, referring to FIGS. 4, 5A, and 5B, the light emitting unit LE, the pinhole PH, and the light receiving element RE of the display device having the optical image sensor according to the embodiment of the present invention are formed. The frames F1 and F2 will be described.

4 is a plan view showing a frame of an optical image formed by light passing through a pinhole of an optical image sensor according to an embodiment of the present invention.

Referring to FIG. 4, light passing through adjacent pinholes PH forms first and second frames F1 and F2 in the light receiving element RE. In FIG. 4, the dotted line is a virtual line showing the area of the light receiving element RE, and is not related to the actual frame image.

5 is a plan view showing a frame of an optical image formed according to a pattern of a light source applied to an optical image sensor according to an embodiment of the present invention, and FIG. 5A is a plan view showing an example of a case where the display pattern for a light source is a rectangle 5B is a plan view showing an example in the case where the display pattern for a light source is circular.

5A and 5B show some examples of display patterns for various light sources, FIG. 5A shows an example of a square display pattern PT1, and FIG. 5B shows an example of a circular display pattern PT2, but the present invention It is not limited, and various display patterns such as polygons may be used in addition to these.

In FIG. 5A, the first frame F1 on the left side represents an image generated when the first square display pattern PT1 generated by the first light emitting portion passes through the first pinhole PH1, and the second side on the right side. The frame F2 represents an image generated when the rectangular display pattern PT2 generated by the second light emitting unit adjacent to the first light emitting unit passes through the second pinhole PH2.

If the turn-on time of the first light-emitting unit is matched with the turn-off time of the second light-emitting unit, and the turn-off time of the first light-emitting unit is matched with the turn-on time of the second light-emitting unit, the first frame F1 of FIG. 5A and the fifth of FIG. Since the two frames F2 can be obtained at different times, the first frame and the second frame do not overlap, so that even if a low-resolution light receiving element is used, an effect of increasing the resolution of the reproduced image can be obtained.

Next, with reference to FIG. 6, image sensing of a display device having an optical image sensor according to an embodiment of the present invention will be described in detail.

6 is a flowchart illustrating a process of sensing an object image using a display device having an optical image sensor according to an embodiment of the present invention.

Referring to FIG. 6, when a finger OB touches or approaches the cover substrate SUB on the top of the display panel DP for the recognition of an object (hereinafter, “touch or proximity of an object” is referred to as “occurrence of an event”) (S100), the display panel (DP) area corresponding to the area where the light-receiving element (RE) of the optical image sensor is disposed is activated.

The light-receiving element RE of the optical image sensor may be disposed corresponding to the entire area of the display panel DP, or may be disposed only in a part of the display panel DP. If the light receiving element RE is disposed corresponding to the entire area of the display panel DP, the touch position or proximity position of the finger OB is determined, and then a specific area of the display panel DP in which the touch or proximity is made is activated. Order.

When the display panel DP is activated by the occurrence of an event, the plurality of light emitting units LE disposed corresponding to the arrangement area of the light receiving element RE are turned on and off. The plurality of light emitting units includes a first light emitting unit RE1 disposed corresponding to the first pin hole PH1 and a second light emitting unit LE2 disposed corresponding to the second pin hole PH2 adjacent to the first pin hole PH1. It includes. The first light emitting part LE1 and the second light emitting part LE2 are alternately turned on and off. For example, when the first light emitting part LE1 is turned on, the second light emitting part LE2 is turned off, and when the second light emitting part LE2 is turned on, the first light emitting part LE1 is turned off. It works.

Accordingly, when the first light emitting part LE1 is turned on, light reflected from the finger OB passes through only the first pinholes PH1 corresponding to the first light emitting part LE1 to enter the light receiving element RE. Therefore, the image of the first frame F1 is acquired and the first light emitting unit LE1 is turned off (S310). When the second light emitting part LE2 is turned on, light reflected from the finger OB passes through only the second pin holes PH2 corresponding to the second light emitting part LE2 and is incident on the light receiving element RE, The image of the second frame F2 is acquired and the second light emitting unit LE2 is turned off (S330).

The image of the first frame F1 and the image of the second frame F2 obtained through the above operation are synthesized, for example, by an image sensing IC to reproduce the finger image of the region where the event is performed (S400). The object image that performed the event is recognized (S500).

Through the above description, those skilled in the art will appreciate that various changes and modifications are possible without departing from the technical idea of the present invention. An optical image sensor according to an embodiment of the present invention includes an electroluminescent display device, a liquid crystal display device (LCD), a plasma display panel (PDP), and a field emission display device (Field) It can be applied to various flat panel display devices such as Emission Display Device (FED), and Electrophoretic Display Device (ED). Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the invention, but should be defined by the claims.

DP: Display panel LE, LE1, LE2: light emitting part
LSL: Light-shielding layer PH, PH1, PH2: Pinhole
RE: Light-receiving element SUB: Cover board

Claims (10)

Cover substrate;
A light receiving element disposed to face the cover substrate and receiving light reflected from a surface of the cover substrate; And
It is disposed between the cover substrate and the light-receiving element, and includes a light-blocking layer having a plurality of pinholes to pass through the light reflected from the cover substrate to guide the light-receiving element,
An optical image sensor having a first distance from the cover substrate to the light blocking layer is less than or equal to a second distance from the light blocking layer to the light receiving element.
According to claim 1,
The plurality of pinholes are spaced apart a predetermined distance, and the adjacent first and second pinholes are formed by a first frame image formed by light passing through the first pinhole and light passing through the second pinhole. Optical image sensor that superimposes the formed second frame image.
According to claim 1,
The plurality of pinholes includes a first pinhole through which the first reflected light reflected from the first area of the cover substrate passes, and a second area of the cover substrate adjacent to the first pinhole and adjacent to the first area of the cover substrate. It includes a second pinhole to pass the second reflected light reflected from,
The third region of the light-receiving element where the first reflected light passing through the first pinhole is received to form a first frame image, and the second reflected light passing through the second pinhole is received to form a second frame image. An optical image sensor partially overlaps a fourth region of the light receiving element.
The method of claim 2 or 3,
The first frame image and the second frame image are optical image sensors that are synthesized after being formed as independent images with a parallax.
A display panel for displaying data;
A cover substrate disposed on a first surface of the display panel;
It is disposed on a second surface opposite to the first surface of the display panel, and includes a light receiving element that receives light reflected from the surface of the cover substrate,
The display panel,
A light emitting unit that emits light toward the cover substrate; And
A display device including a light blocking layer disposed between the light emitting unit and the light receiving element, and having a plurality of pinholes that pass through light emitted from the light emitting unit and reflected by the cover substrate to guide the light receiving element. The method of claim 5,
A display device formed between the plurality of pinholes and the light-receiving element as a light transmitting region.
The method of claim 5,
The plurality of light emitting units are self-emissive display devices that emit light by themselves.
The method of claim 5,
The plurality of pinholes are spaced apart a predetermined distance, and the adjacent first and second pinholes are formed by a first frame image formed by light passing through the first pinhole and light passing through the second pinhole. A display device that superimposes the formed second frame image.
The method of claim 5,
The plurality of pinholes includes a first pinhole through which the first reflected light reflected from the first area of the cover substrate passes, and a second area of the cover substrate adjacent to the first pinhole and adjacent to the first area of the cover substrate. It includes a second pinhole to pass the second reflected light reflected from,
The third region of the light-receiving element where the first reflected light passing through the first pinhole is received to form a first frame image, and the second reflected light passing through the second pinhole is received to form a second frame image. A display device partially overlapping the fourth region of the light receiving element.
The method of claim 8 or 9,
A display device that is synthesized after the first frame image and the second frame image are formed as independent images with a parallax.

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