Patent Application
20110090577
The present invention is from the field of information display devices relating to the implementation of an automobile accessory, such as a ventilation, heating and/or air conditioning installation. Its object is an optical system pertaining to such a display device and said display device.
An automobile is commonly equipped with an accessory, such as a ventilation, heating and/or air conditioning installation for the air contained within the vehicle's passenger compartment, a portable telephone, an onboard computer, a satellite locating system or other similar accessory. The accessory can be almost any equipment, such as an optional appliance which is not essential to a primary and critical function of the vehicle, namely its movement. More particularly, such an accessory is not involved in the implementation of the engine of the vehicle but is likely to control the latter. As an example, the equipment can be a dashboard, or even a speedometer.
Such an accessory commonly comprises a device for displaying at least one information item, such as an information item relating to the implementation of the accessory. In the case where the accessory is an installation of the abovementioned kind, said information item is, for example, a numerical datum, such as the temperature of the air contained in the passenger compartment and/or the desired temperature of said air, or even a pictogram- or icon-type symbol, of the kind representing the outline of the vehicle's passenger compartment. In the case where the accessory is a portable telephone, said information item is, for example, an information item of the telephone number and/or correspondent name kind. In the case where the accessory is an onboard computer or a satellite locating system, said information item is, for example, an alphanumeric character, an icon or a pictogram.
The display device comprises a means of displaying said information item. The display means is notably a display screen with transmissive lighting, reflective lighting and/or transflective lighting. For example, the display means is likely to be a liquid crystal display screen, commonly defined by the acronym “LCD”, a screen comprising an array of thin film transistors, commonly defined by the acronym “TFT”, a vacuum fluorescent screen, commonly defined by the acronym “VFD” or an organic light-emitting diode screen, commonly defined by the acronym “OLED”, or even a fixed symbol.
The display device also comprises a front face for either protecting the display means and/or serving as a surface for projecting said information item. The front face is, for example, a decorative pane designed to protect the display means from the environment outside the display device. The front face is likely to have an irregular and/or granular surface with bumps, notably in the case where it is not polished. The display means and the front face are arranged facing one another, with a space provided between them which is filled with air, the refractive index of which is equal to 1.
The display means is designed to make visible to a user said information item which is generated on the surface of the display means. In the case where the display means is an “LCD” type screen, said screen is associated with at least one light source designed to backlight it, in order to make said information item visible to the user through the front face. The display means is shaped into a flat surface which extends along a general extension plane.
A general problem that arises concerns the fact that the information item displayed on the display means is liable to generate an image projected onto the front face which is blurred for a user looking at said screen through the front face. In order to try to resolve this problem, the document US 2006/0139759 (HASHIMOTO et al) proposes arranging between the display means and the front face an imaging optical system which consists of a plurality of identical lenses divided up into two groups. The lenses of a first group are arranged along a first plane placed facing the screen, and the lenses of a second group are arranged along a second plane placed facing the front face, the second plane being parallel to the first plane. Each lens of the first group has an input face through which incoming light rays originating from the display means penetrate and each lens of the second group has an output face for light rays toward the front face, the incoming light rays passing through said system as far as the corresponding output fade to ultimately reach the front face.
Each lens has an optical axis and two vertices formed at a respective end of the optical axis of said lens. The optical axes of the lenses are oriented parallel to one another, while also being oriented orthogonally on the one hand to the general extension plane of the display means and on the other hand to the first and to the second planes. Moreover, each lens of the first group is placed directly in line with a corresponding lens of the second group. In other words, each lens of the first group is placed facing a corresponding lens of the second group, so that their respective optical axes are identical and that one of the vertices of the lens of the first group is in contact with one of the vertices of the corresponding lens of the second group.
Using a display device equipped with such an imaging optical system presents drawbacks which need to be remedied.
Firstly, in the case where the display device comprises a plurality of light sources, the image of said information item seen by the user through the front face is likely to consist of a plurality of partial images of said information item, which is particularly unsatisfactory for the user.
Furthermore, the viewing angle for a clear image for the user is likely to be restricted. More specifically, a user situated in a peripheral area of the display device cannot clearly view the information, which is restrictive, even dangerous for a user driving the vehicle.
Finally, one or more ghost images of said information item are likely to be projected onto the front face and/or close to the latter. These ghost images are a visual nuisance for the user that should preferably be minimized.
The aim of the present invention is to propose an optical system comprising a plurality of lenses divided up into at least one first group comprising at least two lenses and one second group comprising at least two lenses, at least one lens of the first group being arranged directly in line with a corresponding lens of the second group, said optical system being able to focus an image onto a front face of practically any conformation, without generating ghost images, said image being clear, precise and complete. Another aim of the present invention is to propose a display device comprising such an optical system, such a display device being designed to display an information item relating to the implementation of an automobile accessory and being effective, small and reliable so as to be able to deliver to a user said information item without the latter being distorted or corrupted and without distracting the user by creating visual artifacts.
The optical system of the present invention is an optical system comprising a plurality of lenses divided up into at least one first group comprising at least two lenses and one second group comprising at least two lenses. At least one lens of the first group is arranged directly in line with a corresponding lens of the second group.
According to the present invention, said optical system is equipped with means of channeling light rays entering into any lens of the first group toward the corresponding lens of the second group.
These arrangements are designed to prevent the passage of light rays entering into any lens of the first group toward a lens of the second group other than that arranged directly in line with said lens of the first group. The light rays entering into a lens of the first group are oriented by channeling means toward the corresponding lens of the second group placed directly in line with the lens of the first group, to avoid dispersion of these incoming light rays toward a lens of the second group other than that situated facing the lens concerned of the first group.
The result of this is that an image of said information item, projected onto a front face, is clear, precise and complete. Another result is an absence of ghost images projected onto said front face.
Said channeling means advantageously comprise a main grating which is interposed between the lenses of the first group and the lenses of the second group, the main grating comprising a distal edge bearing against the lenses of the first group and a proximal edge bearing against the lenses of the second group.
The main grating preferentially comprises a plurality of main channels which extend between the distal edge and the proximal edge of said main grating.
Each main channel is advantageously formed directly in line with a corresponding pair of lenses of the first group and of the second group arranged directly in line with one another.
Preferably, each main channel extends longitudinally between a first orifice which covers a lens of the first group and a second orifice which covers the corresponding lens of the second group.
The lenses of the first group are notably arranged along a surface S1 whereas the lenses of the second group are notably arranged along a surface S2.
The surface S1 is, for example, shaped in a first plane P1.
Each lens of the first group preferentially has a first optical axis A1 which is oriented orthogonally to said first plane P1 and in that each lens of the second group has a second optical axis A2 which is also oriented orthogonally to said first plane P1.
The first A1 and second A2 respective optical axes of lenses of the first group and of the second group of one and the same pair are notably identical.
Each main channel advantageously has an axis of symmetry A which is identical to the first A1 and second A2 optical axes.
The main grating is, for example, arranged on a grating plane P′ which is formed parallel to said first plane P1.
The main grating is notably produced from an optically opaque material.
Each main channel advantageously houses a lens of a third group which is identical to the lenses of the first and second groups.
Each lens of the third group preferentially has a third optical axis A3 which is identical to the first A1 and second A2 optical axes.
Each lens of the third group is preferably placed at an equal distance X from the lenses of the first and second groups between which the lens of the third group is interposed.
The lenses of the third group are advantageously arranged on a third plane P3 which is formed parallel to the first plane P1.
The channeling means preferentially comprise at least one secondary grating provided with secondary channels.
Each secondary channel advantageously houses a respective lens of the first group.
Each secondary channel preferably houses a respective lens of the second group.
Each lens of the first group is, for example, arranged directly in line with a respective pixel that the display means comprises.
The display device of the present invention is mainly recognizable by the fact that it is a device for displaying at least one information item comprising a display means, a front face and such an optical system, said display means generating said information item in the form of light rays and being arranged facing the front face, said optical system being interposed between the display means and the front face in order to project said information item onto the front face.
Said surface S1 has, for example, a conformation similar to a conformation C,P″ of the front face.
Said surface S1 also has, for example, a conformation symmetrical to a conformation C,P″ of the front face relative to a plane of symmetry interposed between the front face and the surface S1.
According to a first embodiment, the lenses of the first group are optically different from one another in order to focus an image of said information item on the front face.
According to a second embodiment, the lenses of the second group are optically different from one another in order to focus an image of said information item on the front face.
The front face is, for example, arranged along an incurved line C, the radius of curvature of which is either directed toward the interior of the display device or toward the exterior of the latter.
The first plane P1 is preferably provided parallel to a general extension plane P of the display means.
The present invention will be better understood, and details emerging therefrom will become apparent, from reading the following description of variant embodiments in conjunction with the figures of the appended plates, in which:
In
The display device 1 comprises a display means 4 for displaying the information item 2 and a front face 5 on which the user views an image 6 of said information item 2. The display means 4 is commonly a flat screen which is shaped on a general extension plane P. The display means 4 is a screen of almost any kind, for example of the “LCD”, “TFT”, “OLED”, “VFD” or similar type, and is likely to be equipped with several light sources 7, notably in the case where the screen is of the “LCD” or “TFT” type; the light sources 7 being arranged facing a rear face 8 of the display means 4, in order to allow the latter 4 to be backlit and then enable the information item 2 to be displayed.
Especially to protect the display means 4, the front face 5 is arranged facing a front panel 9 of the display means 4. Generally, the front face 5 covers the display means 4 in order to mask it when it is off, notably for esthetic reasons. Said front face 5 is arranged at a distance D from the display means 4, a space E being provided between the display means 4 and the front face 5. Moreover, notably for esthetic reasons, it is desirable for the front face 5 to be granular and have irregularities, such as bumps and/or pits.
An imaging optical system 10 is interposed between the display means 4 and the front face 5 in order to focus the image 6 of the information item 2 on the front face 5. In general, the imaging optical system 10 is a system of almost any kind able to make light rays 11 entering into the imaging optical system 10 converge at a point of the front face 5. Said imaging optical system 10 comprises at least a plurality of optical lenses 12 which are divided up into a first group 13 of lenses 12 and a second group 14 of lenses 12, a lens 12 of the first group 13 being arranged facing a lens 12 of the second group 14. Thus, the lenses 12 are arranged in pairs 15 of superposed lenses 12 formed by a lens 12 of the first group 13 and by a lens 12 of the second group 14. Each lens 12 of the first group 13 has an optical axis A1 which is oriented orthogonally to the general extension plane P of the display means 4 and each lens 12 of the second group 14 has a second optical axis A2 which is also oriented orthogonally to the general extension plane P of the display means 4. The optical axes A1 and A2 of a pair 15 of superposed lenses 12 of the first group 13 and of the second group 14 are identical.
The lenses 12 of the first group 13 are arranged on a first plane P1 which is formed parallel to the general extension plane P of the display means 4. The lenses 12 of the first group 13 are, for example, arranged directly in line with a respective pixel 16 that the display means 4 comprises. However, the lenses 12 of the first group 13 are likely to be arranged differently relative to the pixels 16 that the display means 4 comprises. It will be understood that, in the plane P1, the lenses 12 of the first group 13 are likely to be arranged relative to one another in almost any mosaic pattern, preferentially hexagonal, or even square or rectangular, in an order from the most optically effective to the least effective.
Each lens 12 has an input face 17 through which the incoming light rays 11 penetrate and an output face 18 through which light rays leave the lens 12. The input face 17 and the output face 18 have a respective vertex defined as a point of the surface of the lens 12 through which the optical axis A1, A2 of the lens 12 passes. Said lens 12 has a thickness L defined as the distance between the two vertices 19 of the lens 12.
Moreover, each lens 12 of the first group 13 is situated at a distance L1 from the display means 4 whereas each lens 12 of the second group 14 is situated at a distance L2 from the projection surface 5. Finally, a lens 12 of the first group 13 is placed at a distance H from the lens 12 of the second group 14 with which it constitutes the pair 15 of superposed lenses 12.
The lenses 12 of the first 13 and of the second 14 groups are either produced from glass by a photolithographic process or a machining process, or from a plastic material based on an injection or press molding method.
Such an imaging optical system 10 has the drawback of delivering to the user an image 6 of the information item 2 which is blurred and/or truncated. Furthermore, ghost images of the desired image of the information item 2 appear on and/or close to the front face 5. Finally, such an imaging optical system 10 is not suitable for a front face 5 of almost any conformation.
This is why it is advantageously proposed by the present invention to equip the imaging optical system 10 with means 20 of channeling incoming light rays 11 within any lens 12 of the first group 13 toward the corresponding lens 12 of the second group 14 with which said lens 12 of the first group 13 forms a pair 15 of lenses 12 facing one another, that is to say, the lens 12 of the second group 14 whose second optical axis A2 is identical to the first optical axis A1 of the lens 12 concerned of the first group 13.
These arrangements mean that the imaging optical system 10 is able to deliver to the user a clear and precise image 6, regardless of the shape and size of the information item 2. These arrangements are also intended to provide a uniform and complete view of the image 6 for the user.
According to a first, a second and a third variant embodiment of the present invention respectively represented in
The main grating 24 is provided with main channels 27 which pass through it from end to end from the distal edge 25 to the proximal edge 26 of said main grating 24. The main channels 27 are parallel to one another and extend longitudinally along an axis of symmetry A which is identical to the first A1 and second A2 optical axes of the lenses 12 of the first 13 and second 14 groups of the pair 15 of corresponding lenses 12.
Each main channel 27 is formed directly in line with a corresponding pair 15 of lenses 12 of the first 13 and of the second 14 groups. More specifically, each main channel 27 is longitudinally delimited by a first orifice 28 which covers a lens 12 of the first group 13 and a second orifice 29 which covers the corresponding lens 12 of the second group 14.
The main grating 24 is produced from an optically opaque material, such that light rays penetrating into a main channel 27 via the first orifice 28 can leave said main channel 27 only via the second orifice 29 of the main channel concerned 27.
These arrangements are such that, based on a covering of the output face 18 of the lenses 12 of the first group 13 and of the input face 17 of the lenses 12 of the second group 14, the incoming light rays 11 within a lens 12 of the first group 13 can be propagated only toward the corresponding lens 12 of the second group 14 with which it forms a pair 15 of superposed lenses 12. Thus, the information item 2 displayed on the display means 4 is reproduced identically on the front face 5 without the appearance of ghost images.
More particularly in
Each lens 12 of the third group 30 has a third optical axis A3 which is identical to the first A1 and second A2 optical axes. Each lens 12 of the third group 30 is placed at an equal distance X from the lenses 12 of the first 13 and second 14 groups between which the lens 12 of the third group 30 is interposed.
According to the variant embodiment represented in
According to a fourth variant embodiment illustrated in
It will be noted that, according to the first, second, third and fourth variant embodiments respectively illustrated in
According to a fifth and a sixth variant embodiment respectively illustrated in
More particularly according to the fifth variant embodiment illustrated in
It will be noted at this point in the description that, according to the variants illustrated previously, the lenses 12, either of the first group 13 or of the second group 14, are identical to one another. On the other hand, according to the sixth variant embodiment illustrated in
According to a seventh variant embodiment illustrated in
| Number | Date | Country | Kind |
|---|---|---|---|
| 07/08807 | Dec 2007 | FR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2008/067675 | 12/16/2008 | WO | 00 | 12/22/2010 |
