KR20190018905A - Flat Panel Display Embedding Optical Imaging Sensor - Google Patents

Abstract

The present invention relates to a flat panel display device with an embedded image sensor such as a fingerprint recognition sensor. According to the present invention, an image recognition sensor with an embedded flat panel display device includes: a display panel; a cover substrate; a low refractive layer; a light incident element; a light source; and a light detecting element. The display panel defines a display area and a non-display area. The cover substrate has a length, a width, and a constant thickness for accommodating the display panel, and is disposed on a top of the display panel. The low refractive layer is arranged in the display area on a lower surface of the cover substrate. The light incident element is arranged in the non-display area on the lower surface of the cover substrate.

Description

Technical Field [0001] The present invention relates to a flat panel display (LCD)

The present invention relates to a flat panel display device incorporating an image sensor such as a fingerprint recognition sensor. More particularly, the present invention relates to a flat panel display device incorporating an optical image sensor including an optical image sensor and a super thin film substrate for providing a directional light.

With the development of computer technology, various kinds of applications such as a notebook computer, a tablet PC, a smart phone, a personal digital assistant, an automated teller machine, a search guide system, A computer based system has been developed. These systems typically store a lot of confidential data, such as business information or business secrets, as well as personal information related to personal life, so there is a need to enhance security to protect these data.

For this purpose, a method of enhancing security using an image sensor capable of recognizing biometric information has been proposed. For example, fingerprint sensors are known that can enhance security by registering or authenticating a system using a fingerprint of a finger. The fingerprint sensor is a sensor that detects a human fingerprint. The fingerprint sensor is roughly classified into an optical fingerprint sensor and a capacitive fingerprint sensor.

The optical fingerprint sensor irradiates light using a light source and detects light reflected by a ridge of the fingerprint through a CMOS (Complementary Metal Oxide Semiconductor) image sensor. Optical fingerprint sensors require additional equipment to scan using light. With known optical scanning devices, there is a limit to increasing the scan area. Therefore, various applications such as coupling with a display device are difficult.

A capacitive fingerprint sensor uses a difference in the quantity of electricity charged between a ridge and a valley in contact with a fingerprint sensor. A conventional capacitive fingerprint sensor is configured in the form of an assembly in combination with a specific push button, and a circuit for measuring the capacitance between the capacitive plate and the user's fingerprint (ridge and valley) .

When a high-resolution sensor array and an IC are formed together using a silicon wafer, a complicated assembly structure is required, thereby increasing a non-display area (bezel area). Further, since a push button (e.g., a home key of a smart phone) and a fingerprint sensor are overlapped, not only the thickness increases but also the fingerprint sensing area depends on the size of the push button.

In order to solve such a problem, a technique of using the area of the touch sensor screen as a fingerprint identification area has been developed. A personal portable display device such as a smart phone is often provided with a protective film for protecting the display panel. When the display area of the personal portable display device is applied as an area for fingerprint recognition, if a protective film is attached, the fingerprint recognition function may significantly deteriorate.

There is an increasing demand for a fingerprint sensor having an ultra-thin structure that is easy to be combined with a display device. However, due to the above-mentioned problems, it is necessary to develop a completely new optical image recognition sensor and a flat panel display device incorporating the same.

It is an object of the present invention to provide a flat panel display device incorporating an ultra-thin film optical image recognition sensor designed to overcome the above problems. It is another object of the present invention to provide an optical image recognition sensor built-in flat panel display device capable of performing image recognition over a large area corresponding to a display area. It is still another object of the present invention to provide an optical image recognition sensor built-in flat panel display device capable of setting an image recognition area in a desired predetermined area in a display area.

In order to achieve the above object, a flat panel display device with an image recognition sensor according to the present invention includes a display panel, a cover substrate, a low refractive layer, an incident element, a light source and a photodetector. The display panel defines a display area and a non-display area. The cover substrate has a length, a width, and a constant thickness for accommodating the display panel, and is disposed on the top of the display panel. The low refraction layer is arranged in the display area on the lower surface of the cover substrate. The light-incident element is arranged in the non-display area on the lower surface of the cover substrate. The light source is arranged to face the light-incident element at one side of the display panel, and provides incident light to the incident point defined on the surface of the light-incident element. The light detecting element is disposed below the low refractive layer.

For example, it further includes a light collimation filter layer disposed between the lower refractive layer bottom surface and the display panel. The light detecting element is disposed inside the display panel and detects light condensed by the light collimating filter layer, which is irregularly reflected downward from the upper surface of the cover substrate.

For example, it further includes a light collimating filter layer disposed on the lower surface of the display panel. The light detecting element is disposed under the light collimating filter layer and is irregularly reflected downward from the upper surface of the cover substrate and detects the light condensed by the light collimating filter layer.

For example, the light-incident element has a holographic pattern that converts incident light into progressed light totally reflected at the interface between the cover substrate and the low refractive layer.

In one example, the progressive light is diffused at a horizontal diffusion angle corresponding to the width of the cover substrate on a horizontal plane formed by the longitudinal direction and the width direction of the cover substrate.

For example, the horizontal diffusion angle corresponds to the angle between the two lines extending from the incident point to the opposite end of the opposite side of the cover substrate, respectively.

In one example, the progressive light has a high collinearity with a vertical diffusion angle of less than 2 degrees, which is an angle of diffusing on a vertical plane formed by the longitudinal direction and the thickness direction of the cover substrate.

In one example, the advancing light has a vertical diffusing angle corresponding to an angle between the first incident angle and the second incident angle on a vertical plane formed by the longitudinal direction and the thickness direction of the cover substrate. The first incident angle has a larger value than the total reflection critical angle at the interface between the cover substrate and the low refractive index layer. The second incident angle has a larger value than the first incident angle.

In one example, the light source is a garden having a cross-sectional shape having a constant diameter, and provides laser light having a high collinearity to the incidence point substantially equal in size to the cross-sectional shape along the traveling distance.

For example, the light source provides diffuse light having a cross-sectional shape of a garden shape, the cross-sectional size of which increases at a constant rate according to the progress distance, as an incident point.

For example, the light source has an elliptical shape in which the major axis of the light source is arranged in the longitudinal direction and the minor axis is arranged in the width direction, and a laser beam having a high collinearity with substantially the same cross- Point.

For example, the light source has an elliptical shape in which the cross-sectional shape is arranged in the longitudinal direction and the minor axis is arranged in the width direction, and the diffused light whose size increases in a constant ratio with the progress distance to provide.

The present invention can provide an optical image recognition sensor built-in flat panel display device having high resolution image recognition capability. The present invention provides an optical image recognition sensor built-in flat panel display capable of recognizing an image over a large area by diffusing and providing an infrared laser having a dot cross-sectional area provided in a point light source by holographic technology to all and / Device can be provided. Further, in the present invention, the protective substrate itself attached to the first surface of the display device can be used as the cover substrate of the directional light substrate according to the present invention. Therefore, even when the optical image recognition apparatus according to the present invention is combined with the display apparatus, the thickness of the display apparatus is not increased.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing the structure of an optical image sensor built-in type display device according to a first embodiment of the present invention. Fig.
2 is a cross-sectional view showing a path of advancing light inside a cover substrate of a display device incorporating an optical image sensor according to a first embodiment of the present invention.
3 is an enlarged cross-sectional view showing the distribution of progressed light inside the cover substrate of the optical image sensor built-in display device according to the first embodiment of the present invention.
4 is a cross-sectional view showing the structure of an optical image sensor built-in type display device according to a second embodiment of the present invention.
5 is a cross-sectional view showing the structure of an optical image sensor built-in type display device according to a third embodiment of the present invention.
6 is a cross-sectional view showing the path of advancing light inside the cover substrate of the optical image sensor built-in type display device according to the third embodiment of the present invention.
7 is an enlarged sectional view showing the structure of an optical image sensor built-in type display device according to a fourth embodiment of the present invention;
8 is a cross-sectional view showing the structure of an optical image sensor built-in type display device according to a fifth embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Like reference numerals throughout the specification denote substantially identical components. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description, a detailed description of known technologies or configurations related to the present invention will be omitted when it is determined that the gist of the present invention may be unnecessarily obscured. In addition, the names of the components used in the following description may be selected in consideration of ease of specification, and may be different from those of the actual product.

≪ Embodiment 1 >

Hereinafter, a first embodiment of the present invention will be described with reference to Fig. 1 is a view showing the structure of an optical image sensor built-in type display device according to a first embodiment of the present invention. 1 is a side view as viewed from an XZ plane, and the lower drawing is a plan view as viewed from an XY plane from above.

1, an optical image sensor built-in type display device according to a first embodiment of the present invention includes a cover substrate CP, a low refraction layer LR, an incident light element CHOE, a light collimation filter layer LCF, And a panel DP. Although not shown in the drawings, the display panel DP further includes a light detecting element.

The display panel DP includes a display area AA and a non-display area NA. The display area AA represents the video information and occupies most of the central portion of the display panel DP. In the non-display area NA, elements for driving the display area AA may be arranged. The non-display area NA may be disposed on one side of the display area AA or surrounding the display area AA.

The cover substrate CP is in the form of a rectangular plate having a substantially rectangular shape and has a length and a width for accommodating the display panel DP. In addition, the cover substrate CP has a certain thickness for the purpose of protecting the display panel DP. In Fig. 1, the length corresponds to the X axis, the width corresponds to the Y axis, and the thickness corresponds to the Z axis.

A low refractive layer (LR) and an incident element (CHOE) are attached to the lower surface of the cover substrate (CP). The light-incoming element CHOE is an optical element which provides an incident light 100 having a dot cross-sectional area provided by the light source LS into the inside of the cover substrate CP. The incident light element CHOE converts the incident light 100 into the traveling light 200 and enters the inside of the cover substrate CP. It is preferable that the progressed light 200 travels from one side of the cover substrate CP to the other side while repeating total reflection inside the cover substrate CP.

The light incident element CHOE is preferably a film having a holographic pattern for converting the incident light 100 into the traveling light 200. The light-incident element CHOE may be a holographic recording film having the same or slightly larger refractive index as the cover substrate CP.

The light-incoming element CHOE may be disposed on the outside or non-display area of the display panel DP. The drawings are shown for the sake of convenience in that they are arranged at the lower side of one side of the outer cover substrate CP of the display panel DP.

Hereinafter, a process in which the incident light 100 is converted into the proceeding light 200 by the light incident element CHOE and proceeds inside the cover substrate CP will be described with reference to FIG. FIG. 2 is a cross-sectional view showing a path of advancing light inside a cover substrate of an optical image sensor built-in type display device according to the first embodiment of the present invention.

The upper surface of the cover substrate CP is in contact with the air layer AIR. Further, the lower surface of the cover substrate CP is in contact with the low refractive layer LR. The cover substrate CP has a refractive index of 1.5 when a material such as glass is used. Therefore, the total reflection critical angle (T _{CP_AIR} ) on the upper surface of the cover substrate CP is 41.8 degrees.

The low refractive layer LR means a layer having a refractive index lower than that of the cover substrate CP. For example, the low refraction layer (LR) may have a refractive index greater than 1.0 and less than or equal to 1.4. The total reflection critical angle (T _{CP_LR} ) on the lower surface of the cover substrate CP is shown in Table 1 according to the refractive index of the low refractive layer LR.

Refractive index of the low refractive layer LR, n The total reflection critical angle at the _bottom surface of the cover substrate CP, T _{CP LR} 1.4 68.96 DEG (about 70 DEG) 1.3 60.07 DEG (about 61 DEG) 1.2 53.13 DEG (about 54 DEG) 1.1 47.16 DEG (about 48 DEG)

The incidence angle of the progressed light 200 is set such that the incidence angle of the progressed light 200 is substantially equal to the angle of incidence of the incident light 200 on the side of the cover substrate CP, Is preferably larger than the total reflection critical angle (T _{CP LR} ) at the lower surface. When this condition is satisfied, the incident angle? Of the proceeding light 200 is naturally larger than the total reflection critical angle T _{CP_AIR} on the upper surface of the cover substrate CP. Therefore, the progressed light 200 advances while totally reflecting within the cover substrate CP.

That is, the incident angle [theta] for the progressed light 200 to satisfy the total reflection condition is determined by the refractive index of the low refractive layer LR. Here, the case where the refractive index of the low refractive layer LR is 1.4 with the greatest refractive index will be described for convenience. In this case, it is preferable that the incident angle (?) Of the progressed light (200) is set to have a value of 70 degrees or more and 80 degrees or less.

Referring again to FIG. 1, a light collimating filter layer (LCF) is laminated on the lower surface of the low refractive layer (LR). The optical collimation filter layer (LCF) may have a size equal to or smaller than that of the low refractive layer (LR). Alternatively, the optical collimation filter layer LCF may be disposed only in an arbitrary area of the display area AA of the display panel DP.

The light collimating filter layer (LCF) is attached on the upper surface of the display panel (DP). In this case, a light detecting element may be further formed inside the display panel DP. For example, when the display panel DP is a liquid crystal display, the lower substrate on which the thin film transistor and the pixel electrode are disposed and the upper substrate on which the color filter is disposed may be bonded together with the liquid crystal layer interposed therebetween. In this case, one photodetecting element can be arranged for each of several thin film transistor groups.

Now, with reference to FIG. 1 again, a description will be given of a process in which the progressed light 200 travels inside the cover substrate CP and an image is recognized. First, the optical path on the vertical plane which is the XZ plane will be described.

The proceeding light 200 starts from one side of the cover substrate CP, i.e., the side near the incidence point IP, and advances toward the opposite side. An image object IM may be disposed on the upper surface of the cover substrate CP. For example, when applied to a fingerprint sensor, the image object IM may be a fingerprint of a person. The fingerprint has a ridge (R) and a bone (V). The ridge portion directly contacts the surface of the cover substrate CP while the valley portion does not contact the surface of the cover substrate CP.

The progressed light 200 that is in contact with the valley (V) portion of the progressed light 200 proceeds in accordance with the total reflection condition. On the other hand, the progressed light 200 contacting the ridge R is divided into the refracted light 500, the totally reflected light 200 and the non-reflected light 300. The ridge (R) corresponds to human skin and the refractive index is about 1.41. That is, a size slightly larger than the low refractive index layer LR. As a result, all the light amount of the progressed light 200 is not totally reflected, and a part thereof is refracted to the ridge portion (R). Further, the other part is totally reflected and proceeds to the progressed light 200. And another portion is diffused downward in the ridge (R) portion.

The reflected light 300 travels downward in a substantially vertical direction, passes through the low refractive layer LR, and enters the display panel DP. As a result, the non-reflected light 300 can be recognized by the light detecting element incorporated in the display panel DP. The shape of the ridge R can be reproduced by analyzing the light amount of the non-reflected light 300 recognized by the light detecting element.

Here, the reflected light 300 is incident in a direction substantially perpendicular to the upper surface of the display panel DP, but is scattered light, so the amount of light may be low. In this case, there may be a problem in reproducing the shape of the ridge R correctly. Therefore, it is preferable to arrange an optical collimation filter (LCF) on the upper surface of the display panel DP capable of condensing the reflected light 300. Particularly, the light collimation filter (LCF) can be formed in a thin film shape and disposed on the entire upper surface of the display panel DP. Alternatively, it may be arranged only in a specific area of the upper surface of the display panel DP. In this case, only the area where the light collimation filter (LCF) is disposed can be set as the fingerprint recognition area.

The light collimation filter (LCF) may have a film shape with microlenses. Alternatively, it may have a film shape in which micro barrier ribs having different refractive indexes are disposed. Alternatively, it may be a film having a holographic pattern that converts diffused light into collimated light.

Next, the optical path on the horizontal plane which is the XY plane will be described. In the first embodiment, when the advancing light 200 is viewed on the XZ plane (or the 'vertical plane') consisting of the longitudinal axis and the thickness axis, the collimated state of the incident light 100 is maintained. On the other hand, it is preferable to have the horizontal diffusion angle (?) In the XY plane (or 'horizontal plane') consisting of the width direction axis and the longitudinal direction axis. This is to set the image detection area to correspond to the area of the cover substrate CP.

On the XZ plane, it is preferable that the progressed light 200 is spread widely so as to correspond to the width of the cover substrate CP. For example, the horizontal diffusion angle? Is a distance between the incident point IP and the light-emitting element CHOE. The horizontal diffusion angle? Is defined by the two line segments connecting the two end points P1 and P2 of the other side of the cover substrate CP, It can be the same as the angle. As another example, the horizontal diffusion angle? May correspond to an inner angle formed by two line segments connecting the end points of the center portion width of the cover substrate CP at the incident point IP.

In the case where the light collimation filter LCF is disposed over the entire display area AA of the display panel DP, a triangular area having the horizontal diffusion angle? Can be defined as a fingerprint recognition sensing area in FIG. When it is desired to set a fingerprint recognition sensing area in only a partial area, only a partial area can be set in the triangular area.

For the sake of convenience, the progressive light 200 has been described as a line segment having no width. The incident light 100 provided by the light source LS substantially has a cross section. That is, the progressed light 200 also has a distribution area in the cover substrate CP with light having a cross section. Referring to FIG. 3, the distribution condition of the progressed light 200 in the cover substrate CP will be described. 3 is an enlarged cross-sectional view showing the distribution of the progressed light inside the cover substrate of the optical image sensor built-in display device according to the first embodiment of the present invention.

For example, the incident light 100 provided by the light source LS can provide laser infrared rays having a cross-sectional shape of a garden shape with a diameter of 0.5 mm. In the case of a laser infrared ray, the cross-sectional shape of the cross-sectional shape has a substantially high collinearity according to the traveling distance of the light. Here, high collimation means that the diffusion angle is smaller than 2 degrees.

In this case, the incident light (200) is converted into an incident angle (?) Of 70 degrees by the light incident element (CHOE). However, the cross section is a laser infrared ray having a garden shape with a diameter of 0.5 mm as the incident light 100. When the thickness of the cover substrate CP is 0.5 mm, the advancing light 200 touches the upper surface of the cover substrate CP for the first time at a position separated from the incident point by 1.37 mm. The progressed light 200 is totally reflected on the upper surface of the cover substrate CP and returned back to the inside of the cover substrate CP. The progressed light 200 is pre-reflected on the lower surface of the cover substrate CP further advanced by 1.37 mm.

When the progressed light 200 advances in this manner, an image detection area is defined in the area of the progressed light 200 that touches the upper surface of the cover substrate CP. In the case of FIG. 3, band shapes having a width of 0.5 mm with a spacing of 1.37 mm are determined as the image detection area. In this case, since the image detection area is divided at a considerable distance, the resolution of the image recognition may be very low or not properly recognized.

In order to prevent such a problem, the size of the cross section of the light source LS may be increased or the thickness of the cover substrate CP may be reduced. It is technically difficult to reduce the thickness of the cover substrate CP, and it is easier to increase the cross-sectional size of the light source LS since various conditions must be taken into consideration. Referring to FIG. 3, when the cross-sectional size of the light source LS is at least 2.74 mm, the progressive light 200 can be irradiated onto the upper surface of the cover substrate CP without voids.

Alternatively, by configuring the cross-sectional shape of the light source LS to have an asymmetrical structure, the progressed light 200 can be irradiated onto the upper surface of the cover substrate CP without voids. For example, the cross-sectional shape may be an X-axis, that is, an elliptical shape in which a long axis is arranged in the longitudinal direction and a Y axis is shortened in the width direction. In this case, the light source LS can provide a laser infrared ray having a high collinearity with substantially the same cross-sectional shape size according to the traveling distance.

≪ Embodiment 2 >

Hereinafter, a second embodiment of the present invention will be described with reference to FIG. 4 is a cross-sectional view showing the structure of an optical image sensor built-in type display device according to a second embodiment of the present invention.

4, an optical image sensor built-in type display device according to a second embodiment of the present invention includes a cover substrate CP, a low refractive layer LR, an incident element CHOE, a display panel DP, A filter layer (LCF) and a light detection sensor (SEP). Compared with the case of the first embodiment, in the second embodiment, the light detection sensor SEP is provided as a separate component, and is particularly attached to the outside of the lower surface of the display panel DP.

A low refractive layer (LR) and an incident element (CHOE) are attached to the lower surface of the cover substrate (CP). The low refractive layer LR is surface-bonded to the upper surface of the display panel DP. The light-incoming element CHOE may be disposed outside one side of the display panel DP. In this case, the light source LS may be arranged to face the light-incoming element CHOE at one side of the display panel DP.

A light collimating filter (LCF) is disposed on the lower surface of the display panel (DP). The light collimation filter (LCF) is preferably arranged so as to cover the display area AA of the display panel DP in a film form. In some cases, it may be disposed only in a partial area of the display panel DP.

A light detecting element (SEP) is disposed under the light collimating filter (LCF). The light detecting element (SEP) can be attached to the surface with the same area as the light collimating filter (LCF) in film form. When the light collimating filter (LCF) is disposed only in a partial area of the display panel (DP), the light detecting element SEP can also be stacked with the same size as the light collimating filter (LCF).

It is preferable that the cover substrate CP, the low refractive index layer LR and the light-incident element CHOE are disposed on the upper side of the display panel DP, as seen in the first and second embodiments. On the other hand, the photodetector element SEP is preferably disposed under the low refractive index layer LR. Further, it is preferable that the optical collimation filter (LCF) is stacked directly on the light detection element (SEP).

It is preferable that the light collimation filter LCF is interposed between the display panel DP and the low refractive index layer LR when the light detecting element is built in the display panel DP. On the other hand, when the light detecting element SEP is disposed separately from the display panel DP and disposed on the lower surface of the display panel DP, the light collimating filter LCF is disposed between the display panel DP and the light detecting element SEP As shown in Fig.

≪ Third Embodiment >

In the first embodiment, a method of increasing the size of the light source LS in order to uniformly irradiate the progressed light 200 without any empty space on the upper surface of the cover substrate CP has been proposed. The third embodiment will be described with reference to Fig. 5, in which the progressive light is uniformly irradiated without any empty space on the surface of the cover substrate, without increasing the size of the light source. 5 is a cross-sectional view showing a structure of an optical image sensor built-in type display device according to a third embodiment of the present invention.

5, an optical image sensor built-in type display device according to a third embodiment of the present invention includes a cover substrate CP, a low refraction layer LR, an incident light element CHOE, a light collimation filter layer LCF, And a panel DP. Although not shown in the drawings, the display panel DP further includes a light detecting element.

The display panel DP includes a display area AA and a non-display area NA. The display area AA represents the video information and occupies most of the central portion of the display panel DP. In the non-display area NA, elements for driving the display area AA may be arranged. The non-display area NA may be disposed on one side of the display area AA or surrounding the display area AA.

The cover substrate CP is in the form of a rectangular plate having a substantially rectangular shape and has a length and a width for accommodating the display panel DP. In addition, the cover substrate CP has a certain thickness for the purpose of protecting the display panel DP. In FIG. 5, the length is represented by the X-axis, the width by the Y-axis, and the thickness by the Z-axis.

A low refractive layer (LR) and an incident element (CHOE) are attached to the lower surface of the cover substrate (CP). The light-incoming element CHOE is an optical element which provides an incident light 100 having a dot cross-sectional area provided by the light source LS into the inside of the cover substrate CP. The incident light element CHOE converts incident light 100 into vertical diffusion progressive light 201 and enters into the cover substrate CP. It is preferable that the vertical diffusion progressive light 201 travels from one side to the other side of the cover substrate CP while repeating total internal reflection within the cover substrate CP.

Also, as shown in the lower portion of FIG. 1, it is preferable that the vertical diffusion progressed light 201 is diffused on the horizontal plane with a horizontal diffusion angle?. Therefore, the light incident element CHOE has a holographic pattern for converting the incident light 100 into a vertical diffusion progressing light 201 having a vertical diffusion angle on a vertical plane and a horizontal diffusion angle? On a horizontal plane It is preferably a film. The light-incident element CHOE may be a holographic recording film having the same or slightly larger refractive index as the cover substrate CP.

The light-incoming element CHOE may be disposed on the outside or non-display area of the display panel DP. The drawings are shown for the sake of convenience in that they are arranged at the lower side of one side of the outer cover substrate CP of the display panel DP.

Hereinafter, a process in which the incident light 100 is converted into the vertical diffusion progressive light 201 by the light incident element CHOE and proceeds inside the cover substrate CP will be described with reference to FIG. FIG. 6 is a cross-sectional view showing a path of progressed light inside a cover substrate of an optical image sensor built-in type display device according to a third embodiment of the present invention.

The vertical diffusion progressive light 201 is light diffused in the XZ plane, that is, on the vertical plane at the vertical diffusion angle (? '). For example, the vertical diffusion progressive light 201 is one of the lights diffused between the first progressed light 200 and the second progressed light 210. The vertical diffusion angle? 'Is an angle between the first incident angle? 1 of the first traveling light 200 and the second incident angle? 2 of the second traveling light 210. Both the first progressed light 200 and the second progressed light 210 satisfy the total internal reflection condition inside the cover substrate CP.

Therefore, it is preferable that both the first incident angle 1 and the second incident angle 2 are larger than the total reflection critical angle T _{CP LR on} the lower surface of the cover substrate CP. The second incident angle [theta] 2 may be larger than the first incident angle [theta] 1. When this condition is satisfied, the first incident angle 1 and the second incident angle 2 are _naturally larger than the total reflection critical angle T _{CP_AIR} on the upper surface of the cover substrate CP. Therefore, the vertical diffusion progressive light 201 advances while totally reflecting within the cover substrate CP.

That is, both of the first incident angle? 1 and the second incident angle? 2 for satisfying the total reflection condition of the first progressed light 200 and the second progressed light 210 are determined by the refractive index of the low refractive layer LR do. Here, the case where the refractive index of the low refractive layer LR is 1.4 with the greatest refractive index will be described for convenience. For example, the first incident angle [theta] 1 may be set at 70 degrees and the second incident angle [theta] 2 may be set at 78 degrees. In this case, the vertical diffusion angle? 'Has a value of 8 degrees.

However, the first incident angle [theta] 1 and the second incident angle [theta] 2 are not limited to these values, but can be variously set according to the refractive index of the low refractive layer LR. For example, referring to Table 1, when the refractive index of the low refractive layer LR is 1.2, the first incident angle 1 can be set to 55 degrees and the second incident angle 2 can be set to 75 degrees. In this case, the vertical diffusion angle? 'May have a value larger by 20 degrees.

Referring to FIG. 5 again, a description will be given of the path and image recognition process of the vertical diffusion progressed light 201 in the cover substrate CP. For convenience, only the optical path on the vertical plane, which is the XZ plane, will be described.

The vertical diffusion progressive light 201 starts from one side of the cover substrate CP, that is, the side near the incidence point IP, and proceeds toward the opposite side. An image object IM may be disposed on the upper surface of the cover substrate CP. For example, when applied to a fingerprint sensor, the image object IM may be a fingerprint of a person. The fingerprint has a ridge (R) and a bone (V). The ridge portion directly contacts the surface of the cover substrate CP while the valley portion does not contact the surface of the cover substrate CP.

In the vertical diffusion progressed light 201, the vertical diffusion progressed light 201 that touches the valley (V) part continues to proceed according to the total reflection condition. On the other hand, the vertical diffusion progressive light 201 that comes into contact with the ridge R is divided into refracted light 501, pre-reflected light 201, and non-reflected light 301. The refractive index of the ridge portion is about 1.41. That is, a size slightly larger than the low refractive index layer LR. As a result, all the light amount is not totally reflected in the vertical diffusion progressed light 201, and a portion is refracted to the ridge (R) portion. Further, the other part is totally reflected and proceeds to the vertical diffusion progressive light 201. And another part becomes the refracted light 301 which is irregularly reflected downward in the ridge portion.

The reflected light 301 proceeds in the substantially downward direction in the substantially vertical direction, passes through the low refractive layer LR, and enters the display panel DP. As a result, the non-reflected light 301 can be recognized by the light detecting element incorporated in the display panel DP. The shape of the ridge R can be reproduced by analyzing the light amount of the non-reflected light 301 recognized by the light detecting element.

Here, the reflected light 301 is incident in a direction substantially perpendicular to the upper surface of the display panel DP, but is scattered light, so the amount of light may be low. In this case, there may be a problem in reproducing the shape of the ridge R correctly. Therefore, it is preferable to arrange an optical collimation filter (LCF) on the upper surface of the display panel DP capable of condensing the reflected light 301. Particularly, the light collimation filter (LCF) can be formed in a thin film shape and disposed on the entire upper surface of the display panel DP. Alternatively, it may be arranged only in a specific area of the upper surface of the display panel DP. In this case, only the area where the light collimation filter (LCF) is disposed can be set as the fingerprint recognition area.

The light collimation filter (LCF) may have a film shape with microlenses. Alternatively, it may have a film shape in which micro barrier ribs having different refractive indexes are disposed. Alternatively, it may be a film having a holographic pattern that converts diffused light into collimated light.

Referring to FIG. 5 again, the first progressed light 200 and the second progressed light 210 are diffused at the vertical diffusion angle? 'As the total progress of the total reflection inside the cover substrate CP progresses. Accordingly, the area where the first progressed light 200 and the second progressed light 210 meet with the cover substrate CP gradually increases. For example, as shown in FIG. 5, after the total reflection is performed 2-3 times, the entire upper surface of the cover substrate CP can be irradiated.

In the third embodiment, the light source LS is a garden having a cross-sectional shape of a certain diameter, and provides a laser beam having a high collinearity with substantially the same cross-sectional shape in accordance with the progress distance as incident light 100 do. In the light incident element CHOE, incident light 100 is converted into vertical traveling light 201 having a vertical diffusion angle? 'And provided. As a result, the vertically pumped light 201 can be uniformly irradiated without any empty area on the upper surface of the cover substrate CP after several total reflection.

It is preferable that the light incident element CHOE diffuses the incident light 100 on the horizontal plane in the XY plane so as to have a horizontal diffusion angle? In the same manner as in the first embodiment.

<Fourth Embodiment>

Hereinafter, a fourth embodiment of the present invention will be described with reference to FIG. In the fourth embodiment, a case is described in which the same light-incoming elements as in the first embodiment are used, but a light source for providing diffused light is used so that the progressed light is uniformly irradiated without any empty space on the surface of the cover substrate. 7 is an enlarged sectional view showing a structure of an optical image sensor built-in type display device according to a fourth embodiment of the present invention.

The optical image sensor built-in type display device according to the fourth embodiment is almost the same as that according to the first embodiment. If there is a difference, the light source LS provides incident light 101, which is a diffuse infrared ray having a cross-sectional shape of a garden shape and whose cross-sectional size increases at a constant rate according to the traveling distance, at the incident point IP. The detailed description of the same other configurations will be omitted.

The diffused incident light 101 means light between the first incident light 100 and the second incident light 110. The first incident light 100 and the second incident light 110 are diffused at an angle of 8 degrees and have a symmetrical structure with respect to a center line. That is, the first incident light 100 may have an incident angle of +4 degrees and the second incident light 110 may have an incident angle of -4 degrees. The diffused incident light 101 may have a garden shape with a cross-sectional area of 0.5 mm. As the light advances, the cross-sectional area of the diffused incident light 101 increases proportionally.

The light-incident element CHOE is the same as that in the first embodiment. For example, the light-incident element CHOE may be a holographic element that converts the light passing through the center line having an incident angle of 0 degrees in the diffused incident light 101 to the vertical diffusion progressive light 201 having an incident angle of 74 degrees. In this case, the light incident element CHOE is formed by the first incident light 100 as the first incident light 200 having the first incident angle 1 and the second incident light 110 as the second incident light 110 having the second incident angle 2, Converted into progressed light 210. As a result, the first incident angle [theta] 1 is converted to 70 degrees, and the second incident angle [theta] 2 is converted to 78 degrees.

In addition, when the diffusion angle of the diffused light provided by the light source LS is symmetrical to 8 degrees, the horizontal diffusion angle phi is 8 degrees as in the lower drawing of Fig. In this case, since it needs to be widely diffused from the upper surface of the cover substrate CP, it is preferable to spread more widely corresponding to the width of the cover substrate CP on the horizontal plane as in the first embodiment. Therefore, the light incident element CHOE is arranged to convert the incident light so that the incident angle of 0 degrees on the vertical plane has an incident angle of 74 degrees and the horizontal direction of the incident light on the horizontal plane corresponds to the horizontal diffusion angle phi corresponding to the width of the cover substrate CP. .

On the other hand, when a material having a refractive index of 1.1 or 1.2 is applied to the low refractive layer LR, it is possible to use a light source LS that provides diffused light having a wider diffusion angle. For example, when the refractive index of the low refractive layer LR is 1.1, it is sufficient that the incidence angle [theta] that can be totally reflected in the cover substrate CP is 50 degrees or more. For example, since the first incident angle [theta] 1 can be set at 50 degrees and the second incident angle [theta] 2 can be set at 88 degrees, a light source LS that provides diffused light having a diffusion angle of about 38 degrees can be used.

In this case, the light-incident element CHOE may be provided with a holographic pattern in which only the central light having an incident angle of 0 degrees is converted so as to have an incident angle of 69 degrees. At this time, even if the horizontal diffusion angle? On the horizontal plane is not considered, the light provided by the light source LS already has a horizontal diffusion angle of 38 degrees. Even if the entire display area of the display panel DP can not be used as the fingerprint recognition area, a sufficient fingerprint recognition area can be ensured even if the fingerprint recognition area is not wide enough to correspond to the width of the cover substrate CP on the horizontal plane .

The vertical diffusion progressed light 201 whose incident angle is changed by the light incident element CHOE is increased in its sectional area while being totally reflected. As shown in FIG. 7, the diameter of the vertically-diffused propagating light 201 is 1.48 mm at the first contact with the upper surface of the cover substrate CP. And then is totally reflected on the lower surface of the cover substrate CP and has a diameter of 3.44 mm at the second contact with the upper surface of the cover substrate CP. Then, the third tangent overlaps the second tangent. That is, after the second total reflection, the vertical diffusion progressed light 201 is uniformly irradiated on the entire surface area of the upper surface of the cover substrate CP without any empty area.

In the fourth embodiment, the light source LS has been described as providing diffused light having a cross section of gauge. However, the light source LS may have an asymmetrical structure. For example, the light source LS may have an elliptical shape in which the sectional shape is an X axis, that is, a major axis is arranged in the longitudinal direction and a minor axis is arranged in the Y axis, that is, the width direction. In addition, diffused light whose size of the ellipse increases at a constant rate according to the distance of light travel can be provided at the incident point IP.

<Fifth Embodiment>

Hereinafter, a fifth embodiment of the present invention will be described with reference to FIG. The fifth embodiment describes a case where the photodetecting device is configured separately from the display panel in the structure using vertical diffusion progressive light. 8 is a cross-sectional view showing a structure of a display device with an optical image sensor according to a fifth embodiment of the present invention.

The basic configuration of the optical image sensor built-in type display device according to the fifth embodiment is almost the same as that of the second embodiment shown in Fig. If there is a difference, the light source is the same as that in the second embodiment, and provides vertical diffusion progressive light in which traveling light converted in the light-emitting element is diffused also in the vertical plane. Alternatively, the light-incident element is the same as that in the second embodiment, and the light source provides infrared rays diffusing at a certain angle.

8, the optical image sensor built-in type display device according to the fifth embodiment of the present invention includes a cover substrate CP, a low refractive layer LR, an incident element CHOE, a display panel DP, A filter layer (LCF) and a light detection sensor (SEP). As in the second embodiment, the photo detecting sensor SEP is provided as a separate component, and is particularly attached to the outside of the lower surface of the display panel DP.

A low refractive layer (LR) and an incident element (CHOE) are attached to the lower surface of the cover substrate (CP). The low refractive layer LR is surface-bonded to the upper surface of the display panel DP. The light-incoming element CHOE may be disposed outside one side of the display panel DP. In this case, the light source LS may be arranged to face the light-incoming element CHOE at one side of the display panel DP.

A light collimating filter (LCF) is disposed on the lower surface of the display panel (DP). The light collimation filter (LCF) is preferably arranged so as to cover the display area AA of the display panel DP in a film form. In some cases, it may be disposed only in a partial area of the display panel DP.

A light detecting element (SEP) is disposed under the light collimating filter (LCF). The light detecting element (SEP) can be attached to the surface with the same area as the light collimating filter (LCF) in film form. When the light collimating filter (LCF) is disposed only in a partial area of the display panel (DP), the light detecting element SEP can also be stacked with the same size as the light collimating filter (LCF).

As described in the first to fifth embodiments, in the display device incorporating the optical image recognition sensor according to the present invention, the cover substrate attached to the outer surface of the display device and the cover substrate attached to one surface of the cover substrate, And an ultra-thin holographic film and a low refractive layer. Therefore, the optical image recognition sensor can be incorporated without affecting the thickness of the display device. In addition, since the progressive light can be uniformly distributed (or scanned) in the entire area of the display panel of the display device, the image can be recognized. Therefore, the image recognition resolution is excellent and the fine image can be accurately recognized as in fingerprint recognition.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

DP: Display panel CP: Cover substrate
LR: low refraction layer CHOE: incident element
LS: Light source LCF: Light collimating filter layer
SEP: light detecting element 100: incident light
200: progressive light 201: vertical diffusion progressive light
300, 301: Reflected light 500, 501: Refracted light

Claims (12)

A display panel in which a display area and a non-display area are defined;
A cover substrate disposed on the display panel, the cover substrate having a length, a width, and a constant thickness for accommodating the display panel;
A low refraction layer disposed on the display area on a lower surface of the cover substrate;
An incident-light element disposed on the non-display area on a lower surface of the cover substrate;
A light source arranged to face the light incident element at the one side of the display panel and to provide incident light to an incident point defined on the surface of the incident light element; And
And a light detecting element disposed under the low refractive layer.
The method according to claim 1,
Further comprising a light collimating filter layer disposed between the lower refractive layer bottom surface and the display panel,
Wherein the light detecting element is disposed inside the display panel and is irregularly reflected downward from an upper surface of the cover substrate and detects light condensed by the light collimating filter layer.
The method according to claim 1,
And a light collimating filter layer disposed on a lower surface of the display panel,
Wherein the light detecting element is disposed under the light collimating filter layer and is irregularly reflected downward from an upper surface of the cover substrate and detects light condensed by the light collimating filter layer.
The method according to claim 1,
The light-
And a holographic pattern for converting the incident light into progressed light totally reflected at an interface between the cover substrate and the low refractive index layer.
5. The method of claim 4,
The progressed light,
Wherein the light is diffused at a horizontal diffusion angle corresponding to the width of the cover substrate on a horizontal plane formed by the longitudinal direction and the width direction of the cover substrate.
6. The method of claim 5,
Wherein the horizontal diffusion angle corresponds to an angle between two lines extending from both the end points of the incidence point and the opposite side edges of the cover substrate.
5. The method of claim 4,
The progressed light,
And a vertical diffusing angle which is an angle of diffusing on a vertical plane formed by the longitudinal direction and the thickness direction of the cover substrate has a high collinearity of less than 2 degrees.
5. The method of claim 4,
The progressed light,
On a vertical plane formed by the longitudinal direction and the thickness direction of the cover substrate,
A first incident angle having a value greater than a total reflection critical angle at an interface between the cover substrate and the low refractive index layer; And
And a vertical diffusion angle corresponding to an angle between the first incident angle and the second incident angle larger than the first incident angle.
5. The method of claim 4,
The light source includes:
Wherein the cross-sectional shape is a garden having a predetermined diameter, and the laser light having a high collinearity with substantially the same cross-sectional shape size as the progress distance is provided to the incidence point.
5. The method of claim 4,
The light source includes:
Wherein the cross-sectional shape of the incidence point is a gauge shape, and the cross-sectional size of the incidence point is increased at a constant rate according to the progress distance.
5. The method of claim 4,
The light source includes:
Wherein the cross-sectional shape is an elliptical shape having a major axis in the longitudinal direction and a minor axis in the width direction, and a laser beam having a high collinearity substantially equal in size to the cross- Flat panel display with built-in image recognition sensor.
5. The method of claim 4,
The light source includes:
Wherein the cross-sectional shape is an elliptical shape having a major axis in the longitudinal direction, a minor axis in the width direction, and a diffuse light whose size increases at a constant rate in accordance with the progress distance, Flat panel display with built-in sensor.

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