KR20070100941A - A relative movement sensor with enclosed housing - Google Patents

Abstract

An optical input device (110), such as a computer mouse or the like, in which the so-called self-mixing effect in a diode laser is used to measure relative movement of the device (110) relative to a surface (120). A housing (112) contains an optical measuring module (114) comprising a laser (3) and detector (4). The housing (112) fully encloses the optical measuring module (114) and comprises a base plate (116) having a transparent window (124) through which the surface (120) is illuminated by the measuring beam (13) and radiation reflected by the surface (120) can return to the laser cavity. Because the housing (112) is fully enclosed, no ESD shielding is required and the device can be made liquid-tight.

Description

Relative movement sensor enclosed in housing {A RELATIVE MOVEMENT SENSOR WITH ENCLOSED HOUSING}

The present invention relates to a relative motion sensor for an optical input device, wherein the relative motion sensor is configured to irradiate a surface of a subject with a measuring laser beam, and to indicate movement along a measurement axis of a selected portion of measurement beam radiation reflected from the subject surface By converting to a signal, the movement of the light input device and the subject relative to each other along at least one measurement axis is measured.

An optical input device comprising such a relative motion sensor is disclosed in European Patent Application EP-A-0942285. This optical input device is, for example, an optical mouse used in a computer configuration for moving a cursor on a computer display or monitor to select a function of a display menu. Such an optical mouse is moved on a mouse pad, for example as in a conventional mechanical mouse.

Many different types of optical measurement modules are known in the art for use with this type of input device. For example, EP-A-0942285 discloses various embodiments of an optical measuring module that performs homodyne detection or heterodyne detection.

Irrespective of the type of optical measurement module employed, commercially available light input devices have apertures in the base plate to allow light to travel from the light source to other surfaces such as tables, mouse mats, etc. and back to the detector. Need to be formed.

Referring to FIG. 1 of the drawings, a typical optical mouse 10 includes a housing 12 in which an optical measurement module 14 is housed. The optical mouse 10 is also provided with a base plate 16 having a plurality of spacers 18 that allow the optical mouse 10 to slide on the surface 2. The base plate 16 is formed with an opening 22 that allows light to travel from the light measuring module 14 to the surface 20 and back to the detector (in the light measuring module 14).

A disadvantage of the opening 22 in the base plate 16 is that it is difficult to shield the electrostatic discharge (ESD) of the electrical circuit 14 within the housing 12.

Electrostatic discharge (ESD) is due to the accumulation of charge on one surface that is suddenly transferred to another surface upon contact. This discharge is typically several thousand volts, and the components of the light measurement module 14 are particularly sensitive to ESD. One of the ways to cope with ESD is to prevent the ESD damage by flowing the ESD, for this purpose, in the case of the optical mouse 10 of FIG. 24 is installed. This makes the base plate more complicated and expensive.

Applicant has invented an improved configuration that overcomes the above-mentioned problems, and an object of the present invention is to provide an optical input device that does not require an ESD shield plate.

According to the present invention, there is provided an optical input device comprising a relative movement sensor for measuring movement of an optical input device relative to a surface, the optical input device comprising a housing defining an enclosure in which an optical measurement module is provided. And the optical measuring module comprises at least one laser having a laser cavity for generating a measuring beam, the housing containing at least a portion of a material that is transparent to the measuring beam and through which the A surface comprising a base irradiated by the measuring beam, at least some of the measuring beam radiation reflected by the surface is reincident to the laser cavity, and the optical measurement module is reflected back to the laser cavity The laser cavity caused by interference of measurement beam radiation and light waves in the laser cavity Operating the measuring means for measuring a change in the, and further includes a means for supplying an electric signal indicative of the difference for use in determining the movement of said light source device to said surface.

As such, since the optical measuring module uses the optical measuring beam, it is not necessary to form an opening in the base of the housing in order to allow the measuring beam to irradiate the surface and to return the reflected measuring beam radiation to the detector. Thereby, there is no need to provide an ESD shielding plate, and the optical input device can be manufactured in a liquid tight structure having obvious advantages.

In one embodiment, the base may comprise a transmissive window or may be integrally formed with or mounted in the transmissive window. Alternatively, the base may actually be formed of a material that is transparent to the measurement beam, and such a configuration has the added advantage of reducing the part score of the device.

Preferably, the base of the housing is arranged and configured such that, in use, the permeable material is spaced apart from the surface. In the first embodiment, one or more spacers or gliders are provided, which makes it easier to slide the device on the surface, as well as keep the base of the device spaced apart from the surface. Alternatively, such permeable portions are at least partially non-planar structures, for example curved or faced, in which case no spacer is required.

The enclosure is advantageously substantially liquid tight.

Indeed, the present invention extends to a housing of an optical input device as described above, wherein the housing comprises an upper shell and a base plate, which can be connected to each other to form an enclosure, the enclosure being Advantageously it is in fact a liquid tight structure.

The invention also extends to a method of manufacturing an optical input device comprising a relative movement sensor for measuring the movement of the optical input device relative to a surface, the method comprising the steps of: providing an optical measurement module in a housing defining an enclosure; Wherein the optical measurement module comprises at least one laser having a laser cavity for generating a measurement beam, the housing including a base at least a portion of which is transparent to the measurement beam; And the optical measuring module is arranged such that the surface is irradiated by the optical measuring beam through the transmissive portion and at least some of the measuring beam radiation reflected by the surface is reincident to the laser cavity, the optical Measurement module,

Measuring means for measuring a change in the operation of the laser cavity caused by interference of reflected measurement beam radiation reentering the laser cavity and light waves in the laser cavity, and determining the movement of the device relative to the surface Means for supplying an electrical signal indicative of said change for use.

Other aspects, including these aspects of the present invention, will become apparent with reference to the embodiments disclosed herein.

1 is a schematic cross-sectional view of an optical input device according to the prior art.

2 is a schematic cross-sectional view of an optical input device according to a first embodiment of the present invention.

3 is a schematic cross-sectional view of an optical input device according to a second embodiment of the present invention.

Referring to FIG. 2 of the drawings, the optical input device 110 according to the embodiment of the present invention includes a housing 112 and a base plate 116, which includes an enclosure in which the optical measuring module 114 is received therein. Define (123).

The method of employing the optical measurement module 114 to measure the relative movement of the input device 110 relative to the surface 120 uses the so-called magnetic mixing effect in a diode laser. This is a phenomenon in which the radiation emitted by the diode laser and re-incident into the cavity of the diode laser induces a variation in the gain of the laser and thus induces the variation in the radiation emitted by the laser. The input device 110 is moved relative to the surface 120 such that the direction of movement has one component in the direction of the laser beam. When the input device 110 moves with respect to the surface 120, the radiation scattered by the surface 120 obtains a frequency different from the frequency of the radiation irradiating the subject due to the Doppler effect. Part of the scattered light is focused on the diode laser by the same lens that focuses the irradiation beam on the subject. Some of the scattered radiation is incident on the laser cavity through the laser mirror, so that interference of light occurs in the laser. This results in a fundamental change in the characteristics of the laser and the emitted radiation. The parameters that change due to the magnetic interaction effect are the power, frequency and line width of the laser radiation and the laser threshold gain. Due to the interference in the laser cavity, the values of these parameters fluctuate at the same frequency as the difference of the two radiation frequencies. This difference is proportional to the component speed of the subject. For that reason, the displacement of the subject, by the speed and time integration of the subject, can be determined by measuring the value of one of the parameters. Such a method is disclosed in International Patent Application Publication WO02 / 037410.

Therefore, referring again to FIG. 2 of the drawings, the optical measurement module 114 provides a carrier for a diode laser, which may be of VCSEL type, and a detector, for example a photodiode. In Fig. 2 a single integrated wafer 3 is shown comprising one diode laser and the corresponding diode, but in practice one or more further lasers and associated detectors may be provided. The diode laser 3 emits a laser or measuring beam 13, which may be visible or infrared light, for example, and the measuring beam 13 must reach the surface 120. However, the opening need not be formed in the base plate 116. Instead, the base plate 116 is formed with a small region 124 that is transparent to the laser light used to generate the measurement beam 13. Since the laser light has a small spectral bandwidth, the small region or window 124 only needs to be transparent to such a small spectral bandwidth; It may be transmissive, absorptive or reflective for all other wavelengths. This area 124 only needs to be of limited optical quality.

In this way, measurement beam 13 is incident on surface 120, and surface 120 reflects and / or scatters beam 13. Part of the beam 13 is scattered in the direction of the irradiation beam 13, which part is converged on the emitting surface of the diode laser by a lens (not shown) and reincident into the cavity of this laser. As described in WO02 / 37410, the radiation returning to the cavity leads to a change in this cavity, thereby in particular to a change in the intensity of the laser radiation emitted by the diode laser. This change can be detected by a photodiode, which converts the radiation change into an electrical signal, which is processed by an electrical circuit (not shown) to produce a measuring beam for the surface 120 ( 13 is used to determine the displacement movement, thereby determining the displacement of the input device 110 relative to the surface 120.

Referring to FIG. 3 of the drawings, the optical input device according to the second embodiment of the present invention is mostly similar to that of the embodiment described with reference to FIG. 2 in the drawings, and the same components are denoted by the same reference numerals. In this case, however, the transmissive region 124 is at least partially non-planar, such as being curved or having a face. As a result, better optical performance and a more robust design are obtained, and in the illustrated embodiment, the spacer 118 (eg, formed of Teflon®) can be omitted. The curved window 124 can in particular contribute to the optical power of the system. The laser may travel through this window closer to the vertical than when the window is planar. As a result, the optical path through the window 124 becomes shorter (i.e., the likelihood of absorption, birefringence, etc.) becomes smaller, and the aberration becomes smaller. In addition, the distance between the surface and the bottom of the device can be increased so that the effects of scratches or dust on the window can be reduced. In addition, there is less possibility of scratch occurrence.

As a matter of course, the spacer or glider 118 is primarily provided so that the device can slide more easily on the work surface. However, this is not essential. In the illustrated embodiment, the glider 118 achieves the additional purpose of providing some space between the transparent window 124 and the surface, especially when the window 124 is planar. However, this is not essential; Instead, the window 124 may be mounted, curved or faced slightly internally with respect to the base plate surface as in the embodiment shown in FIG. 3.

In addition, in the illustrated embodiment, the light input device includes a base plate 116 with a transmissive window 124 provided therein. However, it is of course possible that the base plate 116 itself can only be made of a material that is transparent to the wavelength of the measurement beam. This provides the advantage that the part score for the optical input device is reduced.

The invention is generally applicable to optical input devices including optical mice for desktop computers, keyboards of desktop or laptop computers, remote controls for different devices, mobile phones, and the like, although the invention is intended to be limited to these. It is not.

It should be noted that the above-described embodiments do not limit the present invention, and that those skilled in the art can design many alternative embodiments without departing from the scope of the present invention as defined by the appended claims. . In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Terms such as "comprisiong" and "comprises" do not exclude anything except elements or steps listed in any claim or throughout the specification. Single reference to one component does not exclude the plural reference of these components and the like. The invention may be implemented by hardware comprising several distinct components or may be implemented by a suitably programmed computer. In the device claim enumerating several means, these several means may be implemented in hardware of one and the same item. The simple fact that certain means are mentioned in different dependent claims does not indicate that a combination of these means may not be usefully used.

Claims (10)

An optical input device 110 comprising a relative movement sensor for measuring the movement of the optical input device 110 relative to the surface 120, A housing 112 defining an enclosure 123 provided with an optical measuring module 114 therein, the optical measuring module 114 for generating a measuring beam 13 and having at least one having a laser cavity Laser (3), the housing (112) of which at least a portion (124) is made of a material that is transparent to the measuring beam (13) through which the surface (120) A base 116 irradiated by the measurement beam 13, wherein at least a portion of the measurement beam radiation reflected by the surface 120 is reincident to the laser cavity 120 and the optical measurement module ( 114 includes measuring means 4 for measuring a change in the operation of the laser cavity caused by interference of reflected measurement beam radiation reentering the laser cavity and light waves within the laser cavity, and the surface ( The device for 120 And input means for supplying an electrical signal indicative of said change for use in determining movement of (110). The method of claim 1, The base (116) is an optical input device (110) formed of a material that is transparent to the measurement beam (13). The method of claim 1, The base 116 comprises a portion 124 of material permeable to the measuring beam 13, which portion 124 is mounted to the base 116 or integrally with the base 116. The optical input device 110 is formed. The method of claim 1, The base (116) of the housing (112) is configured to be arranged such that, in use, the transmissive material (124) is spaced apart from the surface (120). The method of claim 2, The transmissive portion 124 is at least partially non-planar light input device 110. The method of claim 5, The transmissive portion 124 is curved or has a surface. The method of claim 4, wherein At least one spacer (118) is provided for keeping the base (116) of the optical input device (110) spaced apart from the surface (120). The method of claim 1, The enclosure (123) is an optical input device (110) that is substantially liquid-tight. As the housing 112 for the optical input device 110 of claim 1, An upper shell and a base plate 116, The upper shell and the base plate (116) are connectable to each other to form the enclosure (123). A method of manufacturing an optical input device 110 comprising a relative movement sensor for measuring the movement of the optical input device 110 relative to the surface 120, Providing a light measurement module 114 in a housing 112 defining an enclosure 123, the light measurement module 114 for generating the measurement beam 13 and having at least one having a laser cavity Laser (3), the housing (112) comprising a base (116) of at least a portion (124) made of a material that is transparent to the measuring beam (13), and the optical measuring module (114) ), The surface 120 is irradiated by the light measuring beam 13 through the transparent material 124, and at least some of the measuring beam radiation reflected by the surface 120 is reflected to the laser cavity. Arranged to be incident, The optical measurement module 114, Measuring means 4 for measuring a change in the operation of the laser cavity caused by interference of reflected measurement beam radiation reentering the laser cavity and light waves in the laser cavity, and for the surface 120 And means for supplying an electrical signal indicative of said change for use in determining movement of said device (110).

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