TWI464627B - Handwriting input apparatus - Google Patents

Description

Handwriting input device

The present invention relates to a handwriting input device, and more particularly to an optical handwriting input device.

Researchers have been studying how to develop a human-machine-friendly interface. Touch technology and handwriting input technology are the products of this research project, which can help people communicate with computers more quickly and effectively. welcome.

At present, there is a handwriting input device having an input pen for inputting text, graphics and the like, and an image capturing device. The optical axis of the optical system of the image capturing device is perpendicular to the input surface, and the input pen is on the input surface. While touching or inputting text and the like, the light emitted by the input pen tip is reflected by the input surface to the image capturing module, and the reflected light is also moved while the input pen moves, and the image capturing module records the reflection. The trajectory formed by the movement of light can analyze the coordinates of the point touched by the stylus or the coordinates of all points passing through the data processing, thereby making a touch response or converting it into a computer identifiable data display.

However, since the optical axis of the image capturing module is perpendicular to the input surface, when the user inputs with the input pen, the user's hand may block the light emitted by the input pen or block the lens or block of the image capturing module. Light spots, so that the image capture module does not work properly.

In view of this, it is necessary to provide a handwriting input device that can effectively prevent the user's hand from blocking light or blocking the image capturing module.

A handwriting input device includes an input pen, an input surface, and an image capturing module, wherein the input pen is used for touching or writing on the input surface, the input surface has a center, and the image capturing module includes An optical system having an optical axis, the image capturing module being higher than the input surface, the optical axis of the optical system intersecting the input surface at an angle θ , and 0°< θ <90° or 90°< θ <180°, the stylus emits light that can be taken by the image capture module to determine the pen down position of the stylus.

Preferably, the image capturing device is supported above the input surface by a supporting unit.

Preferably, the tip of the stylus is provided with a light source to emit light.

Compared with the prior art, the optical axis of the image capturing module of the handwriting input device of the present invention intersects the input surface at an acute angle or an obtuse angle, so that no light is blocked when writing or touching the input surface on the input surface.

The image capturing device is supported above the input surface by the supporting unit so that the image capturing device can sense the light spot on the entire input surface.

Setting the light source at the tip of the stylus helps to accurately position the pen down position of the stylus.

1‧‧‧Handwriting input device

10‧‧‧Input panel

12, 20, 30‧ ‧ image capture module

14‧‧‧Input pen

100‧‧‧ input face

121, 22, 32‧‧‧ Optical system

122, 23, 33‧‧‧ image sensor

123, 230, 330‧‧‧ the sensing surface

141‧‧‧External light emitting diode

102‧‧‧ Side length

1 is a schematic diagram of a handwriting input device provided by a first embodiment of the present invention.

FIG. 2 is a schematic structural diagram of an image capturing module and an input surface in FIG.

FIG. 3 is a schematic structural diagram of an image capturing module and an input surface book in the handwriting input device provided by the second embodiment of the present invention.

4 is a schematic structural diagram of an image capturing module and an input surface in a handwriting input device according to a third embodiment of the present invention.

The invention will now be described in further detail with reference to the accompanying drawings.

Referring to FIG. 1 and FIG. 2 , the handwriting input device 1 provided by the first embodiment of the present invention includes an input panel 10 , an image capturing module 12 and an input pen 14 .

The input panel 10 has an input face 100 that is rectangular. The input face 100 has four sides and a center that form the boundary of the input face 100.

The image capturing module 12 includes an optical system 121 composed of a lens, a diaphragm, and the like, an image sensor 122, a circuit board (not shown), and the like. The optical system 121 has an optical axis I. The image sensor 122 has a sensing surface 123. The sensing surface 123 has a center O. The sensing surface 123 is perpendicular to the sensing surface 123 and the line passing through the center O is sensed. The center normal of face 123. The optical axis I coincides with the central normal II.

The input pen 14 is provided with a light source at its tip end. Of course, it is also possible to provide a light source on the rod-shaped body of the input pen 12 and that can illuminate the input surface. Preferably, the light source is disposed at the tip end of the input pen 14, because the light emitted by the light source will be directly projected to the pen down point of the input pen, and the position is accurate. Therefore, the image capturing device will directly sense the pen point of the input pen 14 without Consider the difference between the pen down position of the input pen 14 and the spot projection position.

The light source can be an infrared light emitting diode 141, and the infrared light emitting diode 141 can emit infrared light. Accordingly, the image capturing module 12 is an infrared image capturing module capable of sensing infrared light.

Preferably, if the dominant wavelength of the infrared light is λ ₀ , the spectral range of the infrared light is controlled at λ ₀ ±0.1 λ ₀ because the infrared light emitted by the infrared light emitting diode 141 is not monochromatic light, and also because Controlling the spectral range of the infrared light to be narrow can effectively sense the image capturing module 12 without being affected by other wavelengths of light. Of course, the image capturing module 12 should have a wavelength of λ ₀ ± The light between 0.1 λ ₀ is most sensitive.

It can be understood that the input pen 14 can also use other wavelengths of light as the light source. Similarly, the spectral range is required to be controlled to be narrow, and does not exceed one tenth of the dominant wavelength around the dominant wavelength.

The image capturing module 12 is higher than the input surface 100, and the optical axis I and the input surface 100 of the image capturing module 12 intersect at an angle θ of 0°< θ <90° or 90°< θ <180°. That is, the intersections are sharp or obtuse. The orthographic projection of the image capture module 12 on the plane of the input surface 100 can be located inside or outside the input surface 100. In the present embodiment, the orthographic projection is located outside of the input face 100 and is adjacent to one of the sides 102 of the input face 100.

The image capturing module 12 can be positioned above the input surface 100 by means of a support frame, so that it can sense the spot on the entire input surface 100.

First, since the entire input surface 100 can be imaged on the image sensor 122, this is equivalent to determining the coordinates of each point of the input surface 100 by "photographing". When the input pen 16 touches the input surface 100 or writes characters and graphics on the input surface 100, the infrared light emitted by the infrared light emitting diode 141 is taken by the image capturing module 12 (actually, the image capturing module 12 Receiving the light reflected by the input surface 100), the image sensing unit of the image capturing module 12 can be imaged, and the coordinates of the pen point of the input pen 14 and the entire input can be input by other components, such as a processor. Face 100 By referring to the imaging point, it is possible to determine which point of the input surface 100 the coordinates of the pen point point fall on. All the coordinates of the pen down point will be connected by the processor, and the response will be expressed as a point operation or input of a message or text.

Compared with the case where the optical axis I is perpendicular to the input surface 100, the infrared light emitted by the infrared light emitting diode 141 will not be hindered by the hand holding the input pen 14, and the image capturing module 12 can take the infrared of the entire input surface 100. Light.

Please refer to the XYZ coordinate axis, and set the length of the side length 102 to L ₁ , and the vertical distance of the orthographic projection of the image capturing module 12 to the side length 102 is L ₂ , and the image capturing module 12 to the input surface 100 The vertical distance is L ₃ , and the angle between the input surface 100 and the optical axis I is θ . After testing, the optimal position of the image capturing module 12 is limited by the following conditions: 0.2 L ₁ < L ₃ <0.6 L ₁ , -0.2 L ₃ < L ₂ < L ₃ , 30° θ 115°, of course, θ is not equal to 90 degrees, wherein the “-” sign indicates that the orthographic projection of the image capturing module 12 falls on the input surface 100. The optimal position of the image capturing module 12 refers to the position of the lens that can capture the infrared light of the entire input surface 100 and the hand holding the input pen 14 does not block the image capturing module 12.

In addition, when the angle θ between the optical axis I of the image capturing module 12 and the normal direction of the input surface 100 is greater than a certain degree, the light emitted by the input pen 14 may undergo keystone distortion during imaging after passing through the optical system 121. For example, one side of the input surface 100 away from the image capturing module 12 will be image-contracted relative to one side of the image capturing module 12, and if this happens, the infrared of some corners of the input surface 100 is indicated. The light cannot be sensed by the image capture module 12, thus forming a sensing dead zone that affects the responsiveness of the handwriting input device.

FIG. 3 is a schematic diagram of an optical path of the image capturing module 20 and the input surface 100 of the handwriting input device provided by the second embodiment of the present invention. The structure and position of the handwriting input device other than the image capturing module 20 are the same as those of the handwriting input device 1.

The image capturing module 20 includes an optical system 22 and an image sensor 23. The optical system 22 has an optical axis III. The image sensor 23 has a sensing surface 230, and the sensing surface 230 has a center. The sensing surface 230 is perpendicular to the center of the sensing surface 230 passing through the center, and the optical axis III is parallel to the central normal IV and spaced apart by L.

Having the optical axis III parallel to the central normal IV is such that the image sensor 23 is offset relative to the optical system 22 such that some of the orientation of the input surface 100 that was originally imaged outside the imaging region of the image sensor 23 is available in the image sensor. 23 imaging, thus, to reduce the impact of keystone distortion.

The specific value of the spacing L is related to the position of the optical system 22 and the image capturing module 20. Preferably, the spacing L is determined by testing or the like during the manufacturing process of the handwriting input device, and does not need to be continuously debugged during use.

FIG. 4 is a schematic diagram of an optical path of the image capturing module 30 and the input surface 100 of the handwriting input device provided by the third embodiment of the present invention. The structure and position of the handwriting input device other than the image capturing module 30 are the same as those of the handwriting input device 1.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Anyone who is familiar with the skill of this case is assisted by the present invention. Equivalent modifications or variations made by the spirit are to be covered by the following patents.

1‧‧‧Handwriting input device

10‧‧‧Input panel

12‧‧‧Image capture module

14‧‧‧Input pen

100‧‧‧ input face

141‧‧‧Infrared light emitting diode

102‧‧‧ Side length

Claims (8)

A handwriting input device is improved in that the handwriting input device comprises an input pen, an input surface, and an image capturing module, wherein the input pen is used for touching or writing on the input surface, and the input surface has a center, and the image is 撷The module includes an optical system having an optical axis, the image capturing module being higher than the input surface, the optical axis of the optical system intersecting the input surface at an angle θ , the input surface being a rectangle, the input surface Having a side length adjacent to the orthographic projection of the image capturing module on the plane of the input surface, and setting the direction from the center to the orthographic projection of the image capturing module to be positive, and vice versa, The length of the side length is L ₁ , and the vertical distance from the orthographic projection of the image capturing module to the side length is L ₂ , and the vertical distance of the image capturing module to the input surface is L ₃ , then 0.2 L ₁ < L ₃ <0.6 L ₁ , -0.2 L ₃ < L ₂ < L ₃ , 30° θ <90° or 90°< θ 115°, the stylus emits light that can be taken by the image capture module to determine the pen position of the stylus. The handwriting input device of claim 1, wherein the image capturing device is supported above the input surface by a supporting unit. The handwriting input device of claim 1, wherein the pen tip of the stylus is provided with a light source to emit light. The handwriting input device of claim 1, wherein: the main wavelength of the light is λ ₀ , the spectral range of the light is λ ₀ ± 0.1 λ ₀ . The handwriting input device of claim 4, wherein the light is infrared light, and the image capturing module is an infrared image capturing module capable of sensing infrared light. The handwriting input device of claim 1, wherein: the image capturing module is further The step includes an image sensor having a sensing surface having a center normal that is parallel to the center normal. The handwriting input device of claim 1, wherein the image capturing module further comprises an image sensor, the image sensor having a sensing surface, the sensing surface having a center normal. The optical axis intersects the central normal. The handwriting input device of claim 7, wherein the sensing surface is parallel to the input surface.