`(12) Patent Application Publication (10) Pub. No.: US 2003/0164895 A1
`
`Viinikanoja et al.
`(43) Pub. Date:
`Sep. 4, 2003
`
`US 20030164895A1
`
`(54) MOBILE TERMANAL DEVICE HAVING
`CAMERA SYSTEM
`
`Publication Classification
`
`(76)
`
`Inventors: Jarkko Viinikanoja, Tampere (Fl);
`Jukka Yrjanainen, Ylojarvi (Fl)
`
`
` (51) Int. Cl.7 .. ......................... H04N 5/225
`
`(52) US. Cl.
`...................... 348/375; 348/211.2; 348/340;
`348/360
`
`Correspondence Address:
`ANTONELLI TERRY STOUT AND KRAUS
`SUITE 1800
`1300 NORTH SEVENTEENTH STREET
`ARLINGTON, VA 22209
`
`(21) Appl. No.:
`
`09/987,849
`
`(22)
`
`Filed:
`
`Nov. 16, 2001
`
`(57)
`
`ABSTRACT
`
`The present invention is a camera system which is usable
`with a mobile terminal. The camera system includes a lens
`module and at least one mechanism for changing optical
`properties by interacting With the lens module. The camera
`system may be built into the mobile terminal or attached
`thereto as an external module.
`
`
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`2]
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`4]
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`1
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`US 2003/0164895 A1
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`Sep. 4, 2003
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`MOBILE TERMANAL DEVICE HAVING CAMERA
`SYSTEM
`
`BACKGROUND OF THE INVENTION
`
`[0001]
`
`1. Field of the Invention
`
`[0002] The present invention relates to a device, method
`and system for enhancing optical properties of a camera
`system of a mobile terminal device. Particularly, the inven-
`tion relates to a device, method and system for enhancing
`optics of a mobile terminal device having a variable camera
`system employing a cover that integrates variable lenses.
`
`[0003]
`
`2. Description of the Prior Art
`
`[0004] The second generation mobile phone systems, such
`as GSM, have significantly increased over the last years. The
`penetration of mobile phones exceeds 80% in countries with
`advanced wireless markets. The second generation mobile
`communication systems are optimized for voice traffic. The
`coming third generation mobile communication system
`enables not only the intermediate standards of the second
`generation mobile communication system but also the han-
`dling of high data rate services and will provide for voice
`traffic as an additional service. Wireless communication will
`
`be extended to further services which are limited by the low
`data rate of the second generation mobile communication
`systems.
`
`[0005] One of the services requiring high data rates will be
`the possibility to transmit and receive high quality images
`and videos. The capability of high data rates allows provid-
`ing this service within acceptable transmission duration and
`acceptable costs.
`
`include
`[0006] Therefore, coming mobile phones will
`digital cameras to take pictures which may be transmitted to
`other participants of the mobile communication system, like
`friends or colleagues or suitable recipients connected in any
`way to the mobile communication system. For example, a
`built-in digital camera will provide the possibility to operate
`video telephony. The number of applications using built-in
`digital cameras and also camera modules plugged into a
`mobile phone are numerous and the possibility of transmit-
`ting pictures will improve the performance of communica-
`tion in an advantageous way. The success of messages
`according to the short message service (SMS) standard
`which enables the transmission of simple low resolution
`pictures may give a hint to the coming success of video and
`picture transmission with high resolution.
`
`[0007] A digital camera built within a mobile phone or
`provided as an external digital camera module plugged to a
`mobile phone will fulfil its function although several restric-
`tions have to be imposed on the digital cameras, such as size,
`weight, power consumption, and the like. Small mobile
`sized phones of low weight fulfil the demands of the market
`and the consumer. Accordingly, additional built-in equip-
`ment or plugged-on equipment will have to fulfil the same
`demands to be acceptable by the users.
`
`[0008] Preferably, CMOS sensors are used as detector
`system for digital cameras. The size of charged coupled
`devices (CCD) allows designing digital cameras of small
`size and low weight. According to size and weight of mobile
`devices, the optics of the digital camera system have to be
`subject to the same restrictions. That means that advanced
`
`optics known from prior stand-alone digital cameras can not
`be used for digital cameras built into mobile terminals. Size
`and weight of advanced optics will exceed the restrictions.
`Therefore, the digital cameras are equipped with fixed focus
`imaging optics which limits the distance for sharp imaging
`to a imaging distance resulting from the design of the fixed
`focus imaging optics. Often the imaging is limited from
`about 50 cm to infinity. Moreover the (horizontal as well as
`also vertical) field of view is fixed to a pre-defined value.
`
`SUMMARY OF THE INVENTION
`
`[0009] Nevertheless, the need of enhanced optics for digi-
`tal cameras for mobile terminals, especially mobile phone,
`enabling taking of pictures at short distances or pictures of
`different fields of view will arise for the user of the camera
`
`system and will be solved by the present invention.
`
`[0010] The present invention provides a device, a system
`and a method to overcome the limitations of a fixed focus
`
`camera system, especially of camera systems built in mobile
`phones.
`
`[0011] The invention provides a mobile terminal device,
`particularly a mobile phone, equipped with a camera system
`comprising a lens module for imaging, and a mechanism for
`changing optical properties of the lens module to adapt the
`optical properties of the whole camera system to a user’s
`requirements.
`
`[0012] The invention also is a part of a housing, such as
`front or back cover or part of the respective covers, with
`integrated mechanism for changing the optical properties of
`a lens module, wherein the lens module operates a camera
`system of a camera system of a mobile terminal device.
`
`[0013] The invention is also a mechanism for changing
`optical properties of a camera system comprising a lens
`module and operated as a camera system of a mobile
`terminal device wherein the mechanism for changing optical
`properties is integrated into a part of a housing.
`
`[0014] The invention is also a method for changing the
`optical properties of a camera system of a mobile terminal
`device, wherein optical properties of a lens module of the
`camera system are changed by using a mechanism for
`changing optical properties. The mechanism for changing
`optical properties is integrated into a part of a housing
`enclosing the camera system of the mobile terminal device.
`
`[0015] The invention is also a system comprising a camera
`system of a mobile terminal device, a part of a housing and
`a mechanism for changing optical properties of the lens
`module of the camera system, wherein the mechanism for
`changing optical properties of the lens module is integrated
`into a part of the housing.
`
`[0016] Overall, the present invention provides the equip-
`ping of mobile terminal devices with standard camera sys-
`tems enabling the user thereof to take pictures. These
`standard camera systems fulfil the basic requirements of low
`cost systems of small size and low weight with overall cost
`efficiency according to the demand of the market segment.
`The standard camera system provides a kind of standard
`imaging covering a major part of user’s requirement for
`taking pictures or scenes with a camera system. Further
`requirements of the lens system of the camera will be met by
`the mechanism for changing optical properties of the lens
`
`8
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`US 2003/0164895 A1
`
`Sep. 4, 2003
`
`module of the camera. The mechanism for changing optical
`properties may be integrated into the detachably connected
`housing or part of a housing to be connected to the camera
`system in case of the user’s needs. This optional extension
`of the camera system provides the possibility to adapt the
`camera to the respective requirements. The extension is
`rapidly exchangeable. Moreover, different extensions may
`be able to adapt to different requirements and the user may
`be able to decide which size and weight may be acceptable
`with respect
`to individual requirements, since advanced
`optics may not meet the need of size and weight of a
`standard camera system.
`
`[0017] According to a first aspect of the invention, a
`mobile terminal device is provided. The mobile terminal
`device has a camera system comprising a lens module a
`mechanism for changing optical properties thereof, wherein
`the mechanism for changing optical properties is adapted to
`cooperate with the lens module. The lens module operates as
`a standard imaging optics to reproduce images detected by
`a detector system included in the camera system. Preferably,
`the camera system comprises a charged coupled device
`(CCD) for reproducing images which are focused by the lens
`module on the CCD. Typically, the lens module may be a
`fixed focus objective permanently integrated in the camera
`system of the mobile terminal device. Conveniently, fixed
`focus objectives have a limited distance range for focusing
`images,
`i.e. from a minimal distance up to infinity, for
`example 50 cm to infinity. Moreover, further properties like
`horizontal and vertical field of view (HFOV or VFOV,
`respectively) underlie the same restrictions. The mechanism
`for changing optical properties of the lens module may
`enable modifying the limited properties of the lens module,
`for example to shorter minimal distance or varying field of
`View.
`
`the mechanism for changing optical
`[0018] Preferably,
`properties may be connected detachably to mobile terminal
`devices or camera systems, respectively. A detachable con-
`nection may employ a different mechanism for changing
`optical properties according to the current requirements for
`taking pictures. This detachable connection may be a special
`snap-in connection which receives and supports the mecha-
`nism for changing optical properties in an appropriate way.
`The snap-in connection may provide additional connections,
`particularly an electrical connection to the electronics of the
`camera system. The electrical connection may comprise
`signal connection for controlling signals and also power
`supply connection.
`
`[0019] Conveniently, a part of a housing enclosing the
`camera system may comprise the mechanism for changing
`optical properties. A part of a housing may be a front cover
`or a back cover. Moreover, a part of the housing may also be
`a part of the front cover or a part of the back cover. The
`mechanism for changing optical properties may be fixed to
`the part of the housing but also detachably connected to the
`part of the housing. The part of the housing may additionally
`comprise connections, particularly an electrical connection
`to the electronics of the camera system. The electrical
`connection may comprise signal connection for controlling
`signals and also power supply connection.
`
`[0020] Additionally, the part of a housing comprising the
`mechanism for changing optical properties may be detach-
`ably connected. An exchange of different mechanisms for
`
`9
`
`changing optical properties may be performed by exchang-
`ing the part of the housing comprising the respective mecha-
`nisms for changing optical properties.
`
`[0021] Preferably, the part of a housing comprises not only
`a mechanism for changing optical properties but an assem-
`bly of a plurality of mechanisms for changing optical
`properties of different characteristics. The assembly com-
`prised by the part of the housing may be changed upon
`actuation in order to enable the co-operating of the different
`mechanisms for changing optical properties with the lens
`module of the camera system. The assembly may also
`comprise additional elements like a simple protecting cover
`for the lens module or a simple plane of glass protecting the
`lens module during without modifying its optical properties.
`
`[0022] Conveniently, the actuation of the assembly may be
`a manual actuation or a motorized actuation or any other
`electrically controlled actuation, e.g. of an assembly of
`variable lenses, by which at least one of the lenses is put into
`an operative position. In order to control electrically the
`mechanisms for changing optical properties additional elec-
`trical connections may be provided which connect
`the
`electronics of the camera system to the mechanism for
`changing optical properties. Moreover, the electrical con-
`nections may comprise a power supply connection for
`motorized functions of the mechanism for changing optical
`properties.
`
`[0023] Additionally, the actuation may be a sliding actua-
`tion. The assembly of the mechanisms for changing optical
`properties may be arranged straight in a row, e.g. by a row
`of adjacent optical lenses which may be interchanged so that
`at least one of the lenses is put into an operative position at
`a time. The different mechanism for changing optical prop-
`erties may be suitably arranged with the camera system and
`the lens module thereof by sliding the whole assembly along
`a corresponding supporting guide.
`
`[0024] Further, the actuation may be a rotating actuation
`with the assembly being arranged on a wheel. Correspond-
`ingly, the different mechanisms for changing optical prop-
`erties may be suitably arranged with the camera system and
`the lens module thereof by rotating the wheel around an axis
`of the wheel, e.g. rotating the wheel having a plurality of
`circumferentially mounted lenses in its periphery along the
`circumference.
`
`[0025] Further, it may be advantageous to connect detach-
`ably the assembly of the plurality of mechanism for chang-
`ing optical properties. A fast and easy exchange of the
`assembly may increase the possibility of usage. In case of
`the arrangement of the mechanisms for changing optical
`properties onto different wheels may be provided. For
`example, a wheel carrying macro and close-up lenses of
`different imaging ratios, or a wheel carrying far-distance or
`telephoto lenses of different magnifications. The number of
`assemblies and the arrangement of different mechanisms for
`changing optical properties is not limited.
`
`[0026] Preferably, the mechanisms for changing optical
`properties of the lens system of the camera system of the
`mobile terminal device may be at least one lens. Lenses set
`in front of a lens module of a camera system enable
`changing of optical properties of the lens module, like focus
`length, field of view, magnification or minimal
`imaging
`distance. The manufacturing of the lenses may be based on
`
`9
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`US 2003/0164895 A1
`
`Sep. 4, 2003
`
`different lens materials. Common materials are polymers or
`different glass substrates but the materials for the lenses is
`not limited to the commonly used ones.
`
`[0027] Conveniently, at least one lens may be a macro
`lens. Usually, the term macro describes an approximately
`1:1 (object size to image size) reproduction of an object by
`an camera system on an imaging plane. Correspondingly, the
`magnification of the imaged object is 1 or higher.
`
`[0028] Additionally, lenses providing a magnification of
`the imaged object higher than approximately 2 are termed as
`close-up lenses which means that the object size to image
`size of the object is 1:2 or smaller. Such a lens may also be
`provided as a mechanism for changing optical properties of
`the lens module of the camera system.
`
`[0029] Moreover, at least one lens may be a far-distance
`lens providing to possibility to image objects at a far
`distance.
`
`the mechanism for changing optical
`[0030] Preferably,
`properties may comprise
`a wide converter or more
`extremely a fisheye lens.
`
`[0031] Further preferably, at least one lens may be an
`electrically variable lens. For example, electrical lenses may
`provide the possibility to modify their focus length by
`applying different voltages. The modification of the optical
`properties of lenses may be preferable since mechanical
`comparable solutions involving several lenses show many
`disadvantages like intricate mechanics of a relative high
`weight.
`
`[0032] All the aforementioned mechanisms for changing
`optical properties may be designed of single lenses but may
`be also designed of several
`lenses wherein an adapted
`combination of lenses provides respective optical properties.
`
`[0033] Conveniently, the mechanism for changing optical
`properties may include the usage of an objective usually
`built-up of several lenses. The objective may be a zoom
`objective providing a selective range of the field of view.
`Usually, field of view may be selected out of the provided
`range of the field of view by a user operation actuated
`manually of electrically, for example by a motorized adjust-
`ment of the field of view.
`
`[0034] Moreover, the objective may be a telephoto objec-
`tive comprising several lenses and providing telephoto pho-
`tography. The telephoto objective may be designed as a
`zoom telephoto objective providing telephotography at dif-
`ferent magnifications.
`
`[0035] Additionally, the mechanism for changing optical
`properties may include the usage of an auto-focusing objec-
`tive usually built-up of several lenses. Objectives compris-
`ing several lenses to provide the desired optical properties
`require often a focusing of the imaged object onto the image
`plane. The focusing may be motorized actuated or actuated
`by a comparable controllable mechanism. The automatic
`actuation of the focusing of objective comprising several
`lenses may be a preferred solution.
`
`[0036] Conveniently, the mechanism for changing optical
`properties may comprise filters. The employment of filters is
`well known in photography. Different filters may improve
`pictures taken by camera systems. For example skylight
`filter reduce the part of blue colour emerged by the sky on
`
`bright days and reduce the part of coming in ultraviolet (UV)
`light or polarization filters may enable to reduce reflection
`and produce brighter colours. Also colored filters may
`improve pictures taken by camera systems of produce spe-
`cial effects.
`
`[0037] Preferably, the camera system is built in the mobile
`terminal device. The mobile terminal device and the camera
`
`system comprising the lens module are enclosed by the same
`housing. The mechanism for changing optical properties of
`the camera system may be integrated in the housing of the
`mobile terminal device comprising the camera system. The
`part of a housing may be a part of the housing of the mobile
`terminal device including the camera system.
`
`the camera system comprising the
`[0038] Additionally,
`lens module may be a separate external module which may
`be plugged to the mobile terminal device for operation of the
`camera system. The camera system is enclosed by its own
`housing. The mechanism for changing optical properties of
`the camera system may be integrated in the housing of the
`external module comprising the camera system. The part of
`a housing may be a part of the housing of the external
`module including the camera system
`
`[0039] Conveniently, the mobile terminal device may be a
`mobile phone according to the known standards of mobile
`communication, such as global system for mobile commu-
`nication (GSM), universal mobile telecommunication ser-
`vices (UMTS), digital communication system (DCS), wide-
`band code division multiple access (WCDMA), IS-136
`(mainly US wireless communication standard),
`IS-95
`(mainly US wireless communication standard) or the like.
`
`[0040] According to a second aspect of the invention, a
`part of a housing comprising a mechanism for changing
`optical properties is provided. The means for changing
`optical properties are adapted to cooperate with a lens
`module of a camera system. A mobile terminal device
`comprises the camera system. The lens module operates as
`a standard imaging optics of the camera system. Preferably,
`the camera system may be a digital camera system com-
`prising a CCD chip for detecting the images. The lens
`module focuses the images on the CCD chip. Typically, the
`lens module may be a fixed focus objective permanently
`integrated in the camera system which is comprised by the
`mobile terminal device. Conveniently, fixed focus objectives
`have a limited distance range for focusing images, i.e. from
`a minimal distance up to infinity, for example from 50 cm to
`infinity. Moreover, further properties like horizontal and
`vertical field of view (HFOV or VFOV, respectively) under-
`lie the same restrictions. The mechanism for changing
`optical properties of the lens module may be able to modify
`the limited properties of the lens module, for example to
`shorter minimal distance or varying field of view.
`
`the mechanism for changing optical
`[0041] Preferably,
`properties may be connected detachably to mobile terminal
`device or camera system, respectively. A detachable con-
`nection may allow employment of different mechanisms for
`changing optical properties according to the current require-
`ments for taking pictures. This detachable connection may
`be a special snap-in connection which receive and support
`the mechanism for changing optical properties in an appro-
`priate way. The snap-in connection may provide additional
`connections, particularly an electrical connection to the
`electronics of the camera system. The electrical connection
`
`10
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`10
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`US 2003/0164895 A1
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`Sep. 4, 2003
`
`may comprise signal connection for controlling signals and
`also power supply connection.
`
`[0042] Additionally, the part of a housing comprising the
`mechanism for changing optical properties may be detach-
`ably connected. A exchange of different mechanisms for
`changing optical properties may be performed by exchang-
`ing the part of the housing comprising the respective mecha-
`nism for changing optical properties. The part of the housing
`may additionally comprise connections, particularly an elec-
`trical connection to the electronics of the camera system.
`The electrical connection may comprise signal connection
`for controlling signals and also power supply connection.
`
`[0043] Preferably, the part of a housing comprises not only
`a mechanism for changing optical properties but an assem-
`bly of a plurality of mechanisms for changing optical
`properties of different characteristics. The assembly com-
`prised by the part of the housing may be changed upon
`actuation in order to enable the co-operating of the different
`mechanisms for changing optical properties with the lens
`module of the camera system. The assembly may also
`comprise additional elements like a simple protecting cover
`for the lens module or a simple plane of glass protecting the
`lens module during without modifying its optical properties.
`
`[0044] Conveniently, the actuation of the assembly may be
`a manual actuation or a motorized actuation or any other
`electrically controlled actuation. In order to control electri-
`cally the mechanism for changing optical properties, addi-
`tional electrical connections may be provided which connect
`the electronics of the camera system to the mechanism for
`changing optical properties. Moreover, the electrical con-
`nections may comprise a power supply connection for
`motorized functions of the mechanism for changing optical
`properties.
`
`[0045] Additionally, the actuation may be a sliding actua-
`tion. The assembly of mechanism for changing optical
`properties may be arranged straight in a row. The different
`mechanisms for changing optical properties may be suitably
`arranged with the camera system and the lens module
`thereof by sliding the whole assembly along a corresponding
`supporting guide.
`
`[0046] Further, the actuation may be a rotating actuation
`with the assembly arranged on a wheel. Correspondingly,
`the different mechanism for changing optical properties may
`be suitably arranged with the camera system and the lens
`module thereof by rotating the wheel around an axis of the
`wheel.
`
`[0047] Further, it may be advantageous to connect detach-
`ably the assembly of the plurality of mechanisms for chang-
`ing optical properties. A fast and easy exchange of the
`assembly may increase the possibility of usage. In case of
`the arrangement of the mechanisms for changing optical
`properties onto a wheel, different wheels may be provided.
`For example, a wheel carrying macro and close-up lenses of
`different imaging ratios, or a wheel carrying far-distance or
`telephoto lenses of different magnifications. The number of
`assemblies and the arrangement of different means for
`changing optical properties is not limited.
`
`the mechanism for changing optical
`[0048] Preferably,
`properties of the lens system of the camera system of the
`mobile terminal device may be at least one lens. Lenses set
`in front of a lens module of a camera system enable
`
`11
`
`changing of optical properties of the lens module, like focus
`length, field of view, magnification or minimal
`imaging
`distance. The manufacturing of the lenses may be based on
`different lens materials. Common materials are polymers or
`different glass substrates but the materials for the lenses is
`not limited to the commonly used ones.
`
`[0049] Conveniently, at least one lens may be a macro
`lens. Usually, the term macro describes an approximately
`1:1 (object size to image size) reproduction of an object by
`an camera system on an imaging plane. Correspondingly, the
`magnification of the imaged object is 1 or higher.
`
`[0050] Additionally, lenses providing a magnification of
`the imaged object higher than approximately 2 are termed as
`close-up lenses which means that the object size to image
`size of the object is 1:2 or smaller. Such a lens may also be
`provided as a means for changing optical properties of the
`lens module of the camera system.
`
`[0051] Moreover, at least one lens may be a far-distance
`lens providing to possibility to image objects at a far
`distance.
`
`the mechanism for changing optical
`[0052] Preferably,
`properties may comprise
`a wide converter or more
`extremely a fisheye lens.
`
`[0053] Further preferably, at least one lens may be an
`electrically activated lens. For example, electrical lenses
`may provide the possibility to modify their focus length by
`applying different voltages. The modification of the optical
`properties of lenses may be preferable since mechanical
`comparable solutions involving several lenses show many
`disadvantages like intricate mechanics of a relative high
`weight.
`
`[0054] All the aforementioned means for changing optical
`properties may be designed of single lenses but may be also
`designed of several lenses wherein an adapted combination
`of lenses provides respective optical properties.
`
`[0055] Conveniently, the mechanism for changing optical
`properties may include the usage of an objective usually
`built-up of several lenses. The objective may be a zoom
`objective providing a selective range of the field of view.
`Usually, field of view may be selected out of the provided
`range of the field of view by a user operation actuated
`manually of electrically, for example by a motorized adjust-
`ment of the field of view.
`
`[0056] Moreover, the objective may be a telephoto objec-
`tive comprising several lenses and providing telephoto pho-
`tography. The telephoto objective may be designed as a
`zoom telephoto objective providing telephotography at dif-
`ferent magnifications.
`
`[0057] Additionally, the mechanism for changing optical
`properties may include the usage of an auto-focusing objec-
`tive usually built-up of several lenses. Objectives compris-
`ing several lenses to provide the desired optical properties
`require often a focusing of the imaged object onto the image
`plane. The focusing may be motorized actuated or actuated
`by comparable controllable means. The automatic actuation
`of the focusing of objective comprising several lenses may
`be a preferred solution.
`
`[0058] Conveniently, the mechanism for changing optical
`properties may comprise filters. The employment of filters is
`
`11
`
`
`
`US 2003/0164895 A1
`
`Sep. 4, 2003
`
`well known in photography. Different filters may improve
`pictures taken by camera systems. For example, a skylight
`filter reduces the part of blue color from the sky on bright
`days and reduces ultraviolet (UV) light or polarization filters
`may enable reduction of reflection and produce brighter
`colors. Also colored filters may improve pictures taken by
`camera systems of produce special effects.
`
`[0059] Preferably, the camera system is built in the mobile
`terminal device. The mobile terminal device and the camera
`
`system comprising the lens module are enclosed by the same
`housing. The mechanism for changing optical properties of
`the camera system may be integrated in the housing of the
`mobile terminal device comprising the camera system. The
`part of a housing may be a part of the housing of the mobile
`terminal device including the camera system.
`
`the camera system comprising the
`[0060] Additionally,
`lens module may be a separate external module which may
`be plugged to the mobile terminal device for operation of the
`camera system. The camera system is enclosed by its own
`housing. The mechanism for changing optical properties of
`the camera system may be integrated in the housing of the
`external module comprising the camera system. The part of
`a housing may be a part of the housing of the external
`module including the camera system.
`
`[0061] Conveniently, the mobile terminal device may be a
`mobile phone according to the known standards of mobile
`communication, such as global system for mobile commu-
`nication (GSM), universal mobile telecommunication ser-
`vices (UMTS), digital communication system (DCS), wide-
`band code division multiple access (WCDMA), IS-136
`(mainly US wireless communication standard),
`IS-95
`(mainly US wireless communication standard) or the like.
`
`the
`[0062] According to third aspect of the invention,
`mechanism for changing optical properties are provided.
`The mechanisms for changing optical properties are adapted
`to cooperate with a lens module of a camera system. A
`mobile terminal device comprises the camera system. The
`lens module operates as a standard imaging optics of the
`camera system. Preferably,
`the camera system may be a
`digital camera system comprising a CCD chip for detecting
`the images. The lens module focuses the images on the CCD
`chip. Typically,
`the lens module may be a fixed focus
`objective permanently integrated in the camera system
`which is comprised by the mobile terminal device. Conve-
`niently, fixed focus objectives have a limited distance range
`for focusing images,
`i.e. from a minimal distance up to
`infinity, for example from 50 cm to infinity. Moreover,
`further properties like horizontal and vertical field of view
`(HFOV or VFOV, respectively) underlie the same restric-
`tions. The mechanism for changing optical properties of the
`lens module may enable modifying the limited properties of
`the lens module, for example to shorter minimal distance or
`varying field of view.
`
`the mechanism for changing optical
`[0063] Preferably,
`properties may be connected detachably to mobile terminal
`device or camera system, respectively. A detachable con-
`nection may allow employment of different mechanisms for
`changing optical properties according to the current require-
`ments for taking images. This detachable connection may be
`a special snap-in connection which receive and support the
`mechanism for changing optical properties in an appropriate
`way. The snap-in connection may provide additional con-
`
`nections, particularly an electrical connection to the elec-
`tronics of the camera system. The electrical connection may
`comprise signal connection for controlling signals and also
`power supply connection.
`
`[0064] Conveniently, a part of a housing enclosing the
`camera system may comprise the mechanisms for changing
`optical properties. A part of a housing may be a front cover
`or a back cover. Moreover, a part of the housing may also be
`a part of the front cover or a part of the back cover. The
`mechanism for changing optical properties may be fixed to
`the part of the housing but also detachably connected to the
`part of the housing. The part of the housing may additionally
`comprise connections, particularl