KR20110051601A - Optical touch system - Google Patents

Abstract

PURPOSE: An optical touch system is provided to increase the sensitivity by dispersing infrared ray to horizontal direction. CONSTITUTION: A recursive reflector(120) reflects an infrared ray of an infrared LED(Light Emitting Diode). A lens(110) projects an infrared ray of the infrared LED to the recursive reflector. An infrared ray pass filter(130) passes through only the infrared ray which is reflected from the recursive reflector. An object lens(140) condenses infrared ray passing through the infrared ray pass filter. A linear sensor(150) receives the condensed infrared ray and detects a touch area between the lens and the recursive reflector.

Description

Optical touch system {

The present invention relates to an optical touch system that can increase the brightness.

Touch screens include resistive, capacitive, optical, ultrasonic, electromagnetic, and vector force methods, each of which has advantages and disadvantages.

In brief, the resistive method is a method in which a transparent conductive film between two substrates is in contact with each other and is the most easily implemented and excellent in performance among the touch screen methods to date, but has a disadvantage of inferior mechanical and environmental reliability. have.

Similar to the optical sensor method, the ultrasonic method has a disadvantage in that it is vulnerable to noise or noise of a factory by determining a position when the acoustic path between the sound wave generating element and the sound wave recognition element is blocked.

The electromagnetic method is based on the principle of generating magnetism and electromotive force of Faraday's law, and calculates coordinates by judging the amount of current flowing through the coil for each position. Since a signal of alternating current must be applied to the coil, a special dedicated pen is needed.

The capacitive method is a method that detects the minute current flowing according to the capacitance change between the sensor electrode and the finger and determines the position. However, the capacitive method is weak in the noise signal, but it is strong in environmental reliability and changes the upper barrier layer. Therefore, there is an advantage that the mechanical reliability can be changed freely.

Since the optical method does not use a film for touch recognition in principle, the transmittance is 100%. In addition, the reflection and the decrease in the luminance, the blurring of the display, etc., which occur when the touch panel of another type is attached do not occur.

The maintenance of transmittance and brightness in a display is an important factor of quality, which is suitable for such high quality display configurations.

In addition, since the optical touch panel is a method of detecting the coordinates of the light blocking method, the optical touch panel is not detected by physical contact or electrical contact, so that the sensor is not loaded. Accordingly, it is highly reliable and is used for factory monitoring, various automation devices, financial terminals, and the like, and does not use materials such as film or ITO protective film, so that durability of wounds or external shocks is large, and thus there is a low possibility of error such as malfunction.

The present invention is to solve the problem that can increase the brightness.

The present invention,

An infrared light emitting diode emitting infrared light;

A retroreflective plate reflecting the infrared rays emitted from the infrared light emitting diode and having the same incident angle and reflecting angle as the infrared rays;

A lens positioned between the infrared light emitting diode and the retroreflective plate and irradiating the infrared light emitted from the infrared light emitting diode onto the retroreflective plate;

An infrared pass filter for passing only infrared rays reflected by the retroreflective plate;

An objective lens for condensing the infrared rays passed through the infrared filter;

There is provided an optical touch system including a linear sensor that receives infrared light collected from the objective lens and detects a touched area between the lens and the retroreflective plate.

According to the present invention, the lens in front of the infrared light emitting diode is configured to focus the infrared light in the vertical direction and to spread the infrared light in the horizontal direction, thereby increasing the brightness of the infrared light emitted from the infrared light emitting diode to reach all the regions of the reflecting surface of the retroreflective plate. It has an effect that can improve the sensitivity.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a schematic diagram of an optical touch system according to an exemplary embodiment of the present invention.

An optical touch system according to an embodiment includes an infrared light emitting diode (100) emitting infrared light; A retroreflective plate (120) reflecting infrared rays emitted from the infrared light emitting diode (100) and having the same incident angle and reflection angle as that of the infrared rays; A lens (110) positioned between the infrared light emitting diode (100) and the retroreflective plate (120) and irradiating infrared rays emitted from the infrared light emitting diode (100) onto the retroreflective plate (120); An infrared pass filter (130) for passing only infrared rays reflected by the retroreflective plate (120); An objective lens (140) for condensing infrared light passed by the infrared light passing filter (130); The infrared light collected by the objective lens 140 is incident, and includes a linear sensor 150 that detects a touched area between the lens 110 and the retroreflective plate 120.

The infrared rays emitted from the infrared light emitting diodes 100 are reflected by the retroreflective plate 120 and are incident to the linear sensor 150.

In this case, when a human finger or a stylus pen is positioned in a predetermined region between the infrared light emitting diode 100 and the retroreflective plate 120, the infrared rays are blocked in the middle by the human finger or the stylus pen. It is not detected by the linear sensor 150.

Therefore, the linear sensor 150 can optically detect the touched area by detecting the coordinate where the human finger or the stylus pen is located. Such coordinate detection will be described in detail in the following description.

In addition, a flat panel display panel is positioned below the infrared light emitting diode 100 and the retroreflective plate 120. When the user touches a specific area of an image displayed on the flat panel, the linear sensor 150 is disposed. A driving signal corresponding to the coordinates detected at) is generated to perform various functions including screen change, volume control, screen movement, screen enlargement and reduction.

The flat panel display panel may be applied to one of a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), an electroluminescence (EL), an organic light emitting diode (OLED), and an electronic paper display panel. have.

Referring to the operation of the optical touch system according to the embodiment, the infrared light emitted from the infrared light emitting diodes 100 is reflected by the retroreflective plate 120 through the lens 110.

In this case, the lens 110 may be designed such that infrared rays transmitted through the lens 110 are formed on the retroreflective plate 120.

That is, the infrared rays through the lens 110 should be substantially matched to the shape of the reflecting surface of the retroreflective plate 120 to prevent light loss.

The infrared rays reflected by the retroreflective plate 120 may pass through the infrared pass filter 130, may be collected by the objective lens 140, and may be incident on the linear sensor 150 to detect a touched area.

2 is a schematic diagram illustrating a state in which an optical touch system according to an embodiment of the present invention is mounted on a flat panel display panel.

The optical touch system 160 is mounted to the front of the flat panel 200.

Therefore, when the user touches a specific region of the flat panel display panel 200 with the fingers of the hand 250 while viewing the image displayed on the flat panel display panel 200, the optical touch system 160 is driven. The coordinates of the touched specific area can be detected.

The optical touch system 160 may be mounted on the flat panel display panel 200 in the form of an optical module.

That is, the infrared light emitting diode 100, the lens 110, the retroreflective plate 120, the infrared pass filter 130, the objective lens 140, and the linear sensor 150 may be integrally formed to form a single optical module. have.

In this case, the infrared light emitting diode 100, the lens 110, the infrared pass filter 130, the objective lens 140, and the linear sensor 150 are positioned in the first region of the single optical module, and the retroreflective plate ( 120 may be configured to be positioned in a second region (region located opposite to the first region) facing the first region.

In addition, the infrared light emitting diode 100, the lens 110, the infrared pass filter 130, the objective lens 140, and the linear sensor 150 may be implemented as one optical module, and the retroreflective plate 120 may be replaced with the other. It can also be implemented with an optical module.

3 is a diagram for describing a method of detecting coordinates of a specific region touched in the optical touch system according to an exemplary embodiment of the present invention.

An optical module composed of an infrared light emitting diode, a lens, an infrared pass filter, an objective lens, and a linear sensor of the optical touch system may be installed in adjacent areas of two or three corners of the flat panel display panel 200.

In FIG. 3, first and second optical modules 161a and 161b are provided in adjacent regions of two corners of the flat panel display panel 200.

In this case, when a predetermined region 250 of the flat panel display panel 200 is touched, infrared rays are blocked from the touched region 250 so that black spots are provided on the linear sensors of the first and second optical modules 161a and 161b, respectively. (Spot) is formed.

4A and 4B, the linear sensors 150a and 150b of the first and second optical modules 161a and 161b are provided with first to n sensing pixels 151, 152, 153, 154 and 155, respectively. The black spot 251 indicating the area 250 is formed on one sensing pixel of the first to n sensing pixels 151, 152, 153, 154 and 155.

Since the linear sensors 150a and 150b of the first and second optical modules 161a and 161b are installed at different positions from the touched area 250, the first optical to which the black spot 251 is formed is formed. The sensing pixels of the linear sensor 150a of the module 161a and the sensing pixels of the linear sensor 150b of the second optical module 161b are likely to be different.

For example, as illustrated in FIG. 4A, the black spot 251 is formed on the second sensing pixel 152 in the linear sensor 150a of the first optical module 161a, and as shown in FIG. 4B, the black spot 251 is formed. The black spot 251 is formed on the fourth sensing pixel 154 in the linear sensor 150b of the second optical module 161b.

Meanwhile, as illustrated in FIG. 3, when the horizontal direction of the flat panel display panel 200 is defined in the x direction and the vertical direction is defined in the y direction, the first optical module 161a of the touched area 250 is defined. The linear sensor of the second optical module 161b in the first area θ1 formed by the connecting line S1 to the linear sensor 150a and the horizontal direction of the flat panel display panel 200, and in the touched area 250. When the second angle θ2 formed by the connecting line S2 and the horizontal direction of the flat panel display panel 200 and the length of the horizontal direction of the flat panel display panel 200 are known up to 150b), Coordinates can be extracted.

The first angle θ1 and the second angle θ2 are changed according to the position of the touched area 250, and corresponding to the first to n sensing pixels of the linear sensors 150a and 150b. 151,152,153,154,155 are subdivided.

That is, each of the first to n sensing pixels 151, 152, 153, 154 and 155 of the linear sensors 150a and 150b corresponds to the changed first angle θ1 and the second angle θ2.

Therefore, when a black spot is formed on one sensing pixel of the first to n sensing pixels 151, 152, 153, 154 and 155 of the linear sensors 150a and 150b of the first and second optical modules 161a and 161b, the first angle ( Since θ1 and the second angle θ2 are known, the coordinates (x, y) of the touched area 250 can be extracted.

In addition, when a predetermined area 250 of the flat panel display panel 200 is touched, the coordinate extraction operation unit may extract the coordinates (x, y) of the touched area 250 in real time by using the above-described method or another method. It may be included in the touch system.

5 is a schematic perspective view illustrating a lens of an infrared light emitting diode front end of an optical touch system according to an exemplary embodiment of the present invention.

The lens 110 in front of the infrared light emitting diode is processed to collect infrared light in the vertical direction and spread the infrared light in the horizontal direction, and the infrared light emitted from the infrared light emitting diode by the lens 100 is applied to the reflective surface of the retroreflective plate. Sensitivity can be improved by increasing the brightness reaching all areas.

To this end, the lens 110 has a horizontal radiation angle θ1 of 90 ° to 98 ° and a vertical radiation angle θ2 of 1 ° to 3 ° with reference to FIGS. 5 and 6.

That is, when the horizontal radiation angle of the lens 110 is smaller than 90 °, an area where infrared rays do not reach the reflective surface of the retroreflective plate exists in the horizontal direction.

In addition, when the horizontal radiation angle of the lens 110 is greater than 98 °, the area irradiated by the infrared rays through the lens 110 out of the reflective surface of the retroreflective plate in the horizontal direction becomes large.

In this case, the horizontal radiation angle of the lens 110 is designed to be 90 ° ~ 98 ° in consideration of the assembly tolerance of the optical touch system.

In addition, when the vertical radiation angle of the lens 110 is less than 1 °, an area where infrared rays do not reach the reflective surface of the retroreflective plate exists in the vertical direction.

When the vertical radiation angle of the lens 110 is greater than 3 °, the infrared rays passing through the lens 110 out of the reflective surface of the retroreflective plate in the vertical direction become larger.

Here, the size of the retroreflective plate is designed in consideration of various factors including the size of the infrared light emitting diode, the size of the lens 110, the retroreflective plate and the linear sensor, and optical matching, but the height of the retroreflective plate is several millimeters in size. Because it is small, it is designed to be 1 ° ~ 3 °.

In addition, the lens 110 may have a rectangular shape (L2> L1 of FIG. 5), and the light exit surface 110a of the lens 110 is convex.

That is, the light exit surface 110a of the lens 110 is convex from one surface 110b in contact with the light exit surface 110a of the lens 110 to the opposite surface 110c of the one surface 110b. It is.

5 and 6 are the optical axes.

Figure 7a is a graph of the optical characteristics of the infrared light emitted from the infrared light emitting diode without a lens in front of the comparative example, Figure 7b is a graph of the optical characteristics of infrared light through the lens of the infrared light emitting diode front applied in the embodiment of the present invention.

That is, since light is focused on 'A3' of FIG. 7B than 'A1' of FIG. 7A, it can be seen that the lens according to the present invention can reduce the vertical radiation angle considerably than the comparative example.

In addition, since light is spread from 'B3' in FIG. 7B to 'B1' in FIG. 7A, it is understood that the lens according to the present invention can spread infrared rays in the horizontal direction than the comparative example.

8 is an exploded perspective view of an optical module of an optical touch system according to an embodiment of the present invention.

In the optical module of the optical touch system, the infrared pass filter 130 and the objective lens 140 are mounted in the first through hole 171 of the cover mold 170 having the first and second through holes 171 and 172. A lens 110 is mounted in the second through hole 172; An infrared light emitting diode (100) optically aligned with the lens (110) and a linear sensor (150) optically aligned with the objective lens (130) are mounted on the guide portion (190); The objective lens 130 is inserted into the through hole 181 of the housing 180 in which the through hole 181 and the step portion 182 are formed, and the guide portion (182) is inserted into the step portion 182. 190 is mounted and configured.

The infrared light emitting diode 100 and the linear sensor 150 are connected to the FPC 191.

Therefore, the infrared pass filter 130, the objective lens 140, the lens 110, the infrared light emitting diode 100, and the linear sensor 150 may be integrated into one optical module.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

1 is a schematic structural diagram of an optical touch system according to an embodiment of the present invention;

2 is a schematic diagram illustrating a state in which an optical touch system is mounted on a flat panel display panel according to an exemplary embodiment of the present invention.

3 is a diagram for describing a method of detecting coordinates of a specific region touched in an optical touch system according to an exemplary embodiment of the present invention.

4A and 4B are views for explaining a linear sensor of an optical touch system according to an embodiment of the present invention.

5 is a schematic perspective view illustrating a lens of an infrared light emitting diode front end of an optical touch system according to an exemplary embodiment of the present invention.

6 is a cross-sectional view illustrating a lens of an infrared light emitting diode front end of an optical touch system according to an exemplary embodiment of the present invention.

7A and 7B are graphs for explaining optical characteristics with and without lens in front of an infrared light emitting diode applied in an embodiment of the present invention.

8 is an exploded perspective view of an optical module of an optical touch system according to an embodiment of the present invention;

Claims (9)

An infrared light emitting diode emitting infrared light; A retroreflective plate reflecting the infrared rays emitted from the infrared light emitting diode and having the same incident angle and reflecting angle as the infrared rays; A lens positioned between the infrared light emitting diode and the retroreflective plate and irradiating the infrared light emitted from the infrared light emitting diode onto the retroreflective plate; An infrared pass filter for passing only infrared rays reflected by the retroreflective plate; An objective lens for condensing the infrared rays passed through the infrared filter; Infrared light collected from the objective is incident, the optical touch system including a linear sensor (Linear sensor) for detecting the touched area between the lens and the retroreflective plate. The method according to claim 1, The lens, An optical touch system that has been engineered to focus infrared radiation in a vertical direction and to spread infrared radiation in a horizontal direction. The method according to claim 1, The lens, Optical touch system with a horizontal radiation angle of 90 ° to 98 ° and a vertical radiation angle of 1 ° to 3 °. The method according to claim 1, The lens, Rectangular shape, The light exit surface of the lens, And convexly formed from one surface of the lens to the opposite surface of the lens to the opposite surface of the lens. The method according to claim 1, And a flat panel display panel positioned below the infrared light emitting diode and the retroreflective plate. The method according to claim 5, The flat panel display panel, Optical touch system, which is one of Liquid Crystal Display (LCD), Field Emission Display (FED), Plasma Display Panel (PDP), Electroluminescence (EL), Organic Light Emitting Diode (OLED) and Electronic Paper Display Panel. The method according to claim 5, And a coordinate extraction calculator configured to extract coordinates of the touched area in real time when a predetermined area of the flat panel display panel is touched. The method according to claim 1, The infrared light emitting diode, the lens, the infrared pass filter, the objective lens and the linear sensor are implemented in one optical module. The method according to claim 8, The optical module, The infrared filter and the objective lens are mounted in a first through hole of a cover mold having first and second through holes, and the lens is mounted in the second through hole; The infrared light emitting diode in optical alignment with the lens and a linear sensor in optical alignment with the objective lens are mounted in a guide portion; And the objective lens is inserted into the through hole of the housing in which the through hole and the step portion are formed, and the guide part is mounted to the step portion.

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