WO2000048114A2

WO2000048114A2 - A computer pointing device

Info

Publication number: WO2000048114A2
Application number: PCT/SG1999/000141
Authority: WO
Inventors: Teng Tiow Tay
Original assignee: TECHVENTURE Pte Ltd
Current assignee: TECHVENTURE Pte Ltd
Priority date: 1999-02-11
Filing date: 1999-12-15
Publication date: 2000-08-17
Anticipated expiration: 2001-08-11
Also published as: AU1903900A; WO2000048114A3

Abstract

A computer pointing device (1) includes a housing (7), a control means movable to control a cursor or pointer, and an optical radiation source (4). The source (4) is coupled to the control means and is adapted to emit an optical signal in response to movement of the control means. The casing (7) includes an optical window which transmits the optical signals emitted by the optical radiation source. The optical path along which radiation from the optical signals pass from the source includes an optical scattering device which is adapted to scatter the optical signals emitted from the optical window.

Description

A Computer Pointing Device

The invention relates to a computer pointing device, and in particular, a wireless pointing device which transmits information relating to the pointing device's state to the computer by means of infrared (IR) light.

Users interact with personal computers (PC) today via a keyboard and a pointing device, the most common of which is a mouse. Both the keyboard and the mouse are normally individually connected to the PC via cables. The term PC is normally used to refer to the IBM compatible type personal computers. Some non-IBM compatible type computers, such as the Macintosh computers, have mice that are connected to the keyboard via a cable. The information received from the mouse is in turn relayed to the computer by a cable connecting the keyboard to the computer.

The operation of the mouse requires the user to move the mouse on a flat surface such as a table-top. The amount of movement of the mouse by the user is then relayed to the PC which in turn moves a cursor on the monitor screen of the PC. The movement of the cursor on the screen is directly related to the movement of the mouse by the user. As the operation of the mouse requires the user to physically move the mouse, the cable connecting the mouse to the computer often becomes a hindrance to the user. Therefore, there is a need for a mouse that does not have connecting cable.

Various wireless mouse systems have been marketed. In these systems, the connecting cable^' needed to relay data from the mouse to the PC is replaced by either an infrared light (IR) or a radio (RF) link. In both cases, the wireless mouse system consists of two parts: (i) a receiver box connected to the PC; and (ii) a wireless mouse.

In the case of an IR link, the mouse contains an IR transmitter module and an IR receiver is coupled by a cable to the PC. Data from the mouse is transmitted by the transmitter to the receiver and, after processing the data into the appropriate format, the data is then relayed by the receiver to the PC.

A similar system is used for the RF link case, except that the IR transmitter and receiver modules are replaced by a RF transmitter module and a RF receiver module, respectively.

The IR wireless mouse has the advantage that it is cheap to manu acture. However, it does not offer an acceptable level of performance. This is because the IR link has a line of sight requirement. If the line-of-sight link between the transmitter and the receiver module is not maintained, the transmitted data will not be received by the receiver. This may occur when the path is blocked by objects, the transmitter light beam is faced away from the receiver module, or the receiver module is faced away from the transmitter light beam. As many PC casings are of the tower type and are not normally placed on the table, it is difficult for a user to establish or maintain a line-of-sight IR link with a receiver on a PC casing. This causes frustration for users of the IR wireless mouse system. The problem is compounded by the fact that as the IR receiver is connected to the PC, it is very likely to be placed at a distance far away from the transmitting mouse.

Therefore, in order to ensure that sufficient light from the transmitter falls on the receiver, the beam of light from the transmitter has to be concentrated into a relatively narrow beam. This makes the link between the transmitter and the receiver highly directional. In the case of a handheld IR remote controller such as a television remote controller, this is not normally an issue as the user usually points the remote controller towards the television. However in the case of a mouse, the movement of the mouse is used to control the movement of the cursor on the computer screen. It is therefore difficult for the user to fulfill both requirements of controlling the cursor through movement of the mouse as well as ensuring that the mouse points towards the receiver. As a result of the above shortcoming, the IR wireless mouse system has, to date, not been commercially successful.

The RF wireless mouse does not have a line of sight requirement and offers an acceptable level of performance. However the RF wireless mouse is expensive to manufacture. Although it has secured a niche market since its launch, its high price has so far prevented its wide spread acceptance.

As used herein, the terms "optical radiation" and "light" refer to electromagnetic radiation in the infrared, visible or ultraviolet regions of the electromagnetic spectrum, unless the context otherwise requires .

In accordance with an aspect of the present invention, there is provided a computer pointing device for controlling a cursor or a pointer on a display device coupled to a computer comprising a housing, a control means movable to control the cursor or pointer and an optical radiation source coupled to the control means, the source being adapted to emit an optical signal in response to movement of the control means, the casing including an optical window which transmits the optical signal emitted by the optical radiation source, and the optical path along which optical signals pass from the source including an optical scattering device which is adapted to scatter the optical radiation emitted from the optical window.

Preferably, the optical radiation source comprises a light emitting diode.

Typically, the optical radiation source is an infrared radiation source .

Preferably, the optical scattering device comprises a textured surface on the optical window.

In accordance with another aspect of the invention, there is provided a computer pointing device system comprising a pointing device in accordance with the first aspect of the invention, and a computer keyboard including an optical radiation detector mounted therein, and the keyboard housing comprising an optical window for transmitting the optical radiation signals emitted by the pointing device to the detector, the detector converting the detected optical radiation signals to electrical signals for transmission to a processing device to a computer to which the keyboard is coupled.

Preferably, the keyboard further comprises an optical scattering device to scatter optical radiation signals transmitted through the keyboard optical window.

Typically, the optical scattering device comprises a textured surface of the optical window in the keyboard housing.

Preferably, the computer pointing device is a mouse,

An example of a computer pointing device system in accordance with the invention will now be described with reference to the accompanying drawings, in which:

Figure 1 shows a keyboard and a mouse incorporating a wireless infrared link; and,

Figure 2 is a bottom view of the keyboard shown in Figure

1.

Figure 1 shows a wireless IR mouse system. It consists of a keyboard 2 and an IR wireless mouse 1. The keyboard 2 is connected to a PC (not shown) by a suitable cable 3. However, alternatively, the keyboard 2 may be connected to the PC by a RF link. In the case of a RF link, the data to be relayed by the keyboard to the PC is sent through a RF transmitter. A RF receiver is then provided on the PC to receive the data from the RF transmitter and relay the data to the PC. For the purposes of the invention, it is immaterial whether the data from the keyboard is relayed to the PC via a cable, a RF link or any other suitable means.

The body casing 7 of the mouse 1 can be any suitable or desired shape. However, the casing 7 is manufactured from any conventional material which is translucent or transparent to infrared light and so the entire casing 7 forms an optical window in the mouse 1. Although Figure 1 shows the whole of the casing 7 forming the optical window, it may only be necessary for a portion of the sides of the casing 7 to be translucent or transparent. Hence, in this example the optical window would form only a portion of the casing 7.

For better performance, the optical window is textured so that IR light is scattered as it passes through the optical window or be reflected from the casing. In any event, texturing a transparent material will make it translucent. The motion and button detection system of the mouse 1 can be that of any commercially available mouse. The signals output from the motion and button detection system are then modulated with a carrier frequency (typical values are in the 30Khz to 500Khz range) before being used to drive one or more infrared light emitting diodes (LEDs) 4. Typically the LEDs 4 are mounted on a printed circuit board (PCB) within the casing of the mouse. The mounting of the LEDs 4 on the PCB is for ease of manufacture. The modulation scheme used can be amplitude shift keying or frequency shift keying, both of which are well known conventional modulation methods.

Therefore, due to the texturing of the translucent/transparent sections of casing of the mouse 1, the light signals from the LEDs 4 are scattered in all directions as they pass through the optical window in the casing 7. Even in directions that are away from the direction in which the LEDs 4 are facing, there will be light as some of the light transmitted through the optical window of the casing 7 will be reflected backwards by the textured surface of the optical window portion of the casing. In this respect, the mouse can be considered as a lighted frosted bulb except of course that the light is infrared, which cannot be detected by the human eye. The keyboard 2 is shown with a conventionally shaped casing. However, as with the mouse 1, the casing can be of any suitable or desired shape. As shown in Figure 2, the keyboard incorporates a commercially available IR receiver 5 which is mounted on a PCB which in turn is mounted on the underside of the keyboard 2 within the bottom section of the casing of the keyboard 2. The bottom section 6 of the casing forms the underside of the keyboard 2 and the lower sections of the side walls. The bottom section 6 is manufactured from a material which is translucent or transparent to the IR light emitted by the mouse 1, and forms an optical window in the keyboard 2. The surface of the bottom section 6 is textured so that light transmitted through the bottom section 6 is scattered in all directions after it passes through the bottom section β.

It is only necessary for a portion of the sides of the keyboard 2 adjacent to the receiver 5 to be translucent or transparent, and therefore, form the optical window in the keyboard 2. However, if desired the entire keyboard casing (both top and bottom sections) could be manufactured from translucent or transparent material which is preferably textured, and therefore, the entire keyboard casing would form the optical window. The receiver 5 detects the data encoded infrared light emitted from the optical window in the casing 7 of the mouse 1. A microprocessor connected to the receiver 5 then decodes the data and sends it to the PC in an appropriate format. In the example shown, this via the cable 3.

As the optical window in the casing 7 of the mouse 1 scatters emitted light in all directions, at least some of the emitted light will be incident on the keyboard 2, irrespective of the position and orientation of the mouse 1 with respect to the keyboard 2. In addition, as the bottom section 6 in the keyboard 2 includes the whole of the lower section of the keyboard casing and the lower portion of the side walls of the keyboard casing, at least some of the light emitted by the mouse 1 will be incident on the bottom section 6. Even if the IR light from the mouse 1 which is transmitted through the bottom section 6 is not directed towards the receiver 5 when it strikes the bottom section 6, the scattering effect of the textured surface of the bottom section 6 causes the incident IR light to scatter in all directions after it enters the inside of the keyboard casing so that at least some of the light incident on the bottom section 6 will be received by the receiver 5. Therefore, irrespective of the position and orientation of the mouse 1 with respect to the keyboard 2, the IR light signals emitted by the mouse 1 will be received by the receiver 5 in the keyboard 2, provided that the mouse 1 is not too far away from the keyboard 2. Preferably, the mouse 1 and the keyboard 2 are used on the same flat surface to enhance the reliability of reception of the IR light signals by the receiver 5. However, in some situations the receiver 5 will still receive the IR light signals from the mouse 1 even if the mouse 1 and the keyboard 2 are not on a flat surface, or are on different surfaces .

In use, the mouse 1 and keyboard 2 would be used in the same manner as a conventional mouse and keyboard. However, as the mouse is operated by a user, the signals from the mouse's motion and button detection system are modulated onto a carrier frequency, as described above, and then used drive the LEDs 4. The IR light signals emitted by the LEDs 4 are transmitted out of the mouse 1 via the optical window in the casing 7. At least some of the scattered IR light signals from the mouse pass through the optical window 6 and are detected by the IR receiver 5. The receiver 5 converts the IR light signals into electrical signals and outputs them to the PC to via the keyboard cable 3. Due to the scattering of the IR light as it exits the optical window in the casing 7, the intensity of light emitted from the mouse 1 is weak compared to a focused beam of light. Accordingly, the IR light receiver 5 which detects the IR light emitted from the optical window 4 in the mouse 1 must be relatively close to the mouse 1. Typically, the receiver 5 must be no more than approximately 1.5m from the optical window. During normal operation the mouse 1 would be used within an arm's length of the keyboard 2. Hence, during normal use the mouse 1 would be sufficiently close to the keyboard 2 to permit the emitted IR light to be detected by the receiver 5 in the keyboard 2.

Although the invention is described particularly in relation to being used with a computer mouse, this is only an example and the invention could be used with other computer pointing devices, such as a trackball.

Claims

1. A computer pointing device for controlling a cursor or a pointer on a display device coupled to a computer comprising a housing, a control means movable to control the cursor or pointer and an optical radiation source coupled to said control means, said optical radiation source being adapted to emit an optical signal in response to movement of said control means, said casing comprising an optical window which transmits the optical signal emitted by said optical radiation source, and the optical path along which the optical signals pass from said source including an optical scattering device which is adapted to scatter the optical signals emitted from said optical window.

2. A computer pointing device according to claim 1, wherein said optical radiation source comprises a light emitting diode.

3. A computer pointing device according to claim 1 or claim 2, wherein said optical radiation source is an infrared radiation source .

4. A computer pointing device according to any of the preceding claims, wherein said optical scattering device comprises a textured surface on said optical window.

5. A computer pointing device according to any of the preceding claims, wherein a portion of said housing forms said optical window.

6. A computer pointing device according to any of the preceding claims, wherein the entire housing forms said optical window.

7. A computer pointing device system comprising a computer pointing device according to any of claims 1 to 6; and a computer keyboard having a housing and including an optical radiation detector mounted therein, and said keyboard housing comprising a second optical window for transmitting the optical radiation signals emitted by said pointing device to said detector, said detector converting the detected optical radiation signals to electrical signals for transmission to a computer to which said keyboard is coupled.

8. A system according to claim 7, wherein said keyboard further comprises a second optical scattering device to scatter optical radiation signals transmitted through said second optical window.

9. A system according to claim 8, wherein said second optical window comprises a textured surface which forms said second optical scattering device.

10. A system according to any of claims 7 to 9, wherein a portion of said keyboard housing forms said second optical window.

11. A system according to any of claims 7 to 10, wherein the entire keyboard housing forms said second optical window.