WO2013045784A1

WO2013045784A1 - Rigid housing with slender lip for electronic apparatus

Info

Publication number: WO2013045784A1
Application number: PCT/FR2012/052017
Authority: WO
Inventors: Henri Crohas
Original assignee: Archos
Priority date: 2011-09-29
Filing date: 2012-09-10
Publication date: 2013-04-04
Also published as: FR2980906A1; FR2980906B1; CN202435730U

Abstract

The invention relates to a housing for electronic apparatus, comprising at least one front part and one rear part that are shaped so as to be assembled together while delimiting an interior volume able to receive functional components of the apparatus, these functional components comprising at least one screen visible from outside through a window. According to the invention, at least the front part comprises:- a reinforcing framework at least partially integrated by overmoulding into a chassis made of plastic or of metal that can be injected, this reinforcing framework ensuring structural rigidity of the housing, and - a metallic sheet disposed firmly on the chassis and comprising a lip on the outside of the housing, this lip covering a part of the screen in such a way as to constitute the rim of said window.

Description

"Thin lip case for electronic device."

The present invention relates to an electronic device housing, comprising at least a front portion and a rear portion shaped to be joined to each other by defining an interior volume adapted to receive functional components of the apparatus, these functional components. comprising at least one screen visible from the outside through a window. The invention finds a particularly interesting application in computers of the "tablet" or "touch pad" type.

However, the invention is of a broader scope since it relates to the field of electronic devices of any size especially devices comprising a screen such as telephones, players and / or multimedia recorders, laptops, televisions etc. .

Electronics manufacturers are continually seeking to reduce the size of devices in all their dimensions especially in their thickness. They also seek to substantially coplanar surfaces of the components of the front of the devices. In addition, manufacturers are looking for solutions to reduce costs both in terms of material cost and manufacturing cost.

Solutions for obtaining a refined aesthetic and maximizing the surface of the screen in the front face are particularly sought after. This concerns portable electronic devices as well as sedentary devices such as computer screens, ultra-flat TVs designed for wall mounting up to 40 inches diagonal and more.

Conventional solutions are known for making plastic housings, which leads to thick housings.

In such solutions, the housing has two plastic parts: a rear portion and a front portion forming a volume in which electronic components, such as an LCD screen, are disposed. This screen can be covered with a capacitive slab or touch screen panel ("Touch Screen Panel" in English). The front of the housing has a window leaving the visible and accessible screen. Generally, the edge of this window, called "lip" or "Bezel" in English-language publications, is unsightly because it is a plastic lip of more than one millimeter covering the peripheral edge of the screen. In addition, the structural rigidity of the assembly is low when the entire housing is plastic.

A rigidified case is known by adding a machined glass of very high quality and very high resistance that is placed on the touch screen. On the aesthetic aspect, the plastic case is flushly positioned on the outer surface of the lens. On the aspect rigidity, this glass, sometimes called "cover lens", "cover glass" or "Gorrila® glass" in English language is of a great thickness of the order of 1.4mm. The plastic case is glued to a lower part of this glass. The problem of such a system is the excessive cost of the housing assembly and "cover lens".

Solutions are also known for making metal sheet housings or injected metal, this leads to relatively expensive boxes and this requires non-standard solutions to coplanar the surfaces of the screen and the front face. The patent application US 2004/102230 further discloses a solution using plastic elements and metal elements. Known mixed solutions are complex to implement and expensive in tooling.

The present invention relates to a new housing having a very thin edge of the screen so as to provide a very good appearance. Another object of the invention is an inexpensive housing while having a high structural rigidity.

At least one of the aforementioned objectives is achieved with an electronic device housing, comprising at least a front portion and a rear portion shaped to be joined to each other by defining an interior volume adapted to receive functional components of the device. the apparatus, these functional components comprising at least one screen visible from the outside through a window. According to the invention, at least the front part comprises:

a reinforcement frame at least partially integrated by overmoulding in a frame made of plastic material or injectable metal, this reinforcing frame ensuring a structural rigidity of the housing, and

- A metal sheet disposed firmly on the frame and having a lip outside the housing, this lip covering a portion of the screen so as to form the rim of said window. With the housing according to the invention, the edge of the window revealing the touch screen is a metal foil lip which can be very thin so as to be pleasing to the eye and have a very neat finish. This lip thickness may be less than or equal to 0.2 mm, preferably less than or equal to 0.1 mm.

The structural rigidity is ensured by the addition of a reinforcing frame which is a piece of metal, resin, carbon fiber or other, partially integrated by overmolding in the frame. This reinforcing frame is shaped and sized to reach a given level of moments of inertia. These moments of inertia are measured along a torsion axis perpendicular to the screen and along a torsion axis parallel to the plane of the screen. This reinforcing frame is distinct from the metal sheet. It is advantageously formed by a separate part of the metal sheet.

Preferably, the reinforcing frame is in particular inside the housing and invisible from the outside. It can be located between the overmolding plastic, the metal sheet and the electronic components, without for example being directly in contact with the metal sheet.

With the present invention, it is possible to use a thin metal foil of the order of 0.1 mm with a reinforcing frame, the assembly constituting an aesthetically pleasing casing of structural rigidity and inexpensive.

According to an advantageous characteristic of the invention, the lip constitutes a flat frame and the metal sheet further comprises a peripheral rim partially integrated by overmoulding in the frame, this peripheral rim having a non-zero angle with respect to the flat frame.

The peripheral flange is thus inclined with respect to the plane frame, this angle of inclination being preferably a function of the angle of injection of plastic into a mold during overmolding. By way of example, the injection angle is defined so that the axis of the plastic injection flow is in a plane containing this peripheral rim. Therefore, it avoids any distortion that may occur during a high pressure overmoulding and high temperature.

According to other advantageous features of the invention, the lip and the frame are arranged substantially flush, in particular coplanar, at the angle between the peripheral rim and the lip. This provides a very high quality finish with a very pleasant aesthetic appearance. Advantageously, to further avoid any distortion during overmolding, provides a depth of penetration of the peripheral flange in the chassis less than or equal to 2mm.

When not using a peripheral edge inserted by overmolding in the plastic, it is expected to stick the metal sheet on the frame after overmolding the reinforcing frame. The overmoulding of the reinforcing frame makes it possible to constitute a rigid frame whose geometry does not deform. The bonding of the metal foil is carried out on the frame on a planar location which can be machined after overmolding or obtained directly during overmolding.

According to other advantageous features of the invention, there is provided a gap between a portion of the metal sheet and the reinforcing frame, this gap is not filled by the overmolding plastic. However, it is possible to provide a means in the interstice to join a portion of the metal sheet to the reinforcing frame, this means being an adhesive sheet or a spot weld.

According to other advantageous features of the invention, the reinforcing frame may be shaped in the shape of "U" or "V", the closed side of the "U" or "V" being oriented towards the metal sheet.

According to other advantageous features of the invention, the metal sheet has bores and / or indentations located on the peripheral rim, at least partially traversed by plastic or injectable metal. These holes make it possible to ensure a good maintenance of the metal sheet.

In the same way, the reinforcing frame comprises holes and / or indentations traversed at least in part by plastic or injectable metal.

According to one embodiment of the invention, the housing is sized for a screen whose size is between 6.5 and 15 inches.

According to other advantageous features of the invention, the front and rear parts comprise abutments and / or centering ribs shaped to ensure a joined assembly of their adjacent peripheral edges.

With the use of a plastic frame, it is advantageous to have at least one antenna in the plastic frame, this antenna being connected to certain functional components of the electronic device. For example, one can have an antenna embedded in the plastic chassis on each side of the screen when the latter is in landscape mode in particular.

The invention also makes it possible to simplify and reduce assembly operations. Indeed, the invention makes it possible to perform in one operation housing half-shells ready for final assembly. To do this, it is possible to use pre-decorated sheets and plastics dyed in the mass appropriately and including, where appropriate, the functional elements. Surface treatments specific to the interior of the molds can also be implemented to create effects, for example to reduce or accentuate the contrast between the metal surfaces and the plastic surfaces. Of course it is possible to add a finishing step, consisting for example of painting the entire composite part without departing from the scope of the invention. Other advantages and features of the invention will appear on examining the detailed description of a non-limiting embodiment, and the appended out-of-scale drawings, in which:

- Figure 1 is a simplified schematic view of a tablet according to the invention;

- Figure 2 is a simplified sectional view of an inner portion of a tablet according to the invention;

FIG. 3 is a simplified view of a method of injecting plastic into a mold;

Figure 4 is a simplified view of a tablet according to the invention in an alternative embodiment wherein the lip is glued to the frame;

Figure 5 is a simplified top view of a tablet according to the invention; and

Figure 6 is a schematic sectional view at the reinforcing frame of a tablet according to the invention.

In Figures 1 to 6, the various elements common to the various variants or embodiments have the same references.

Of course, the different characteristics, forms and variants of the invention may be associated with each other according to various combinations to the extent that they are not mutually exclusive.

FIG. 1 shows a multimedia electronic device comprising a housing provided with two half-shells 3 and 4, arranged to be assembled by their joint plane 13 and fixed by delimiting an interior volume intended to accommodate functional elements of the 'apparatus.

We will also mention in the remainder of the presentation the "front part 3" and "rear parts 4" to discuss the half-shells also corresponding to the upper and lower faces of the device.

According to one aspect of the invention, at least one of the front 3 and / or rear portions 4 comprises at least one corresponding reinforcing frame, made in a first material, this reinforcing frame being integrated by overmolding in a corresponding frame, realized in a second matter, different from the first.

In the following description, we will describe an embodiment using a metal sheet, a metal reinforcement frame 3 mm thick, and a frame made of a plastic material. More broadly, and while remaining within the scope of the invention, the metal sheet and the reinforcing frame may be made of a steel, or any other metal or metal alloy having a high melting temperature, for example a melting temperature. close to that of steel. The second material is an organic material or a metal or metal alloy having a lower melting temperature than the first material, for example a melting temperature of a magnesium type metal or a Zamac type alloy. One aspect of the invention is to inject the second material into a mold at a temperature below the melting temperature of the metal sheet and the reinforcing frame.

In the example illustrated in Figure 1, we see a touch pad 1 type small computer without keyboard or mouse in the form of a tablet whose screen has a size of about seven inches. This tablet comprises a housing 2 consisting of two parts: a front part 3 and a rear part 4. These two parts define a central volume 5 in which electronic components are arranged. The rear part 4 is a lower box which can be made entirely of plastic or an insert Overmolding integrated metal in a plastic or injected metal frame.

The front portion 3 is a ring directly engaging the rear portion 4 so as to constitute said housing in the form of an open box. The front part 3 comprises:

a plastic frame 30,

a metal sheet 6 emerging on the outside of the frame 30, this metal sheet being an open frame in its central part to thus form a central window 7, in particular rectangular, and

a reinforcing frame 8 disposed below the metal sheet 6 and forming a closed loop around the central volume 5. The metal sheet 6 and the reinforcing frame 8 are partially integrated in the frame 30 of plastic material.

Note that the metal sheet 6 forms a part of the outer skin of the tablet and thus has a look and finish worked according to the desired visual and tactile rendering (decoration, inscription, brushed metal appearance etc.).

By way of nonlimiting example, the central volume 5 comprises on the upper part a touch screen TSP 9 accessible to the user by means of a stylus or a finger via the window 7. There is then a screen of LCD display 10, then a PCB PCB 11 containing at least one microprocessor and memory means (not shown) and a battery 12 to power the assembly.

The housing may comprise complementary functional elements that are in direct relationship with it, such as for example:

an antenna element (metal subassembly, printed circuit, etc.), this type of element being in direct relationship with the housing according to the invention in that the location and / or the characteristics of the antenna element count of the earth plane or planes consisting of the metal parts of the housing and / or the fixing points of the elements in a plastic part, and

light guides for conveying light emitted by sources such as LEDs positioned at advantageous locations in technical and / or economic terms from a printed circuit to places of advantageous rendering in terms of ergonomics and / or aesthetics on the case ...

These functional elements can be incorporated in the casing during the molding of the plastic of the front and rear parts.

The metal foil 6 is made in a sheet metal element having a thickness of 0.1 mm. A thickness of this size makes it possible to minimize the material cost of the metal. A sheet so fine does not necessarily offer as such, the characteristics of robustness sought. The rigidity and durability of a perfect flatness is achieved in particular by adding the reinforcing frame 8 in a screen-box system taken as a whole. The reinforcing frame 8 seals the touch screen 9 and display 10.

The metal foil may be made by any method or by any combination of methods which may include, for example, cutting, stamping, punching, folding, etc.

Referring to Figure 2, we see a little more detail integration of the reinforcing frame in the housing 2 arranged so that the touch screen 9 is in a horizontal plane, the face upward. Note that the metal sheet 6 has a lip 6a visible from the outside and forming a frame of the window 7, and a peripheral flange 6b bent at an angle between 0 and 90 °, substantially 45 ° for example, forming an angle bracket It is difficult to control the dimensional characteristics of an injected metal-plastic composite housing using a small amount of material in that the stresses in the plastic naturally tend to deform the metal sheet. To reduce the impact of shrinkage phenomena, it has been provided during overmoulding to inject the plastic in a flow whose axis is in the plane containing the peripheral rim 6b.

For the sake of clarity, the functional components of the apparatus 1, with the exception of the touch screen 9, have not been shown. For example, it is intended to incline the plane frame 15 by one or two degrees relative to the horizontal (plane of the screen) so that this flat frame comes to press forcefully on the touch screen 6.

The reinforcing frame 8 has a three-part shape. A first vertical portion 8a delimits the central volume 5 laterally. We see a carcass 16 of the LCD screen 10, this carcass being fixed on both sides, on the four lateral sides of the reinforcing frame 8. A second part 8b of the reinforcing frame is horizontal, almost parallel and located below a portion of the plane frame 15 of the metal sheet 6. A third portion 8c is inclined at an angle of substantially 45 ° relative to the second portion 8b , so that the assembly 8a, 8b and 8c constitutes a "U" or a "V" returned downwards. This third part 8c is partially integrated in the plastics material frame 30.

The invention provides for the multiplication of the attachment points between the peripheral flange 6b and the plastics material frame 30 on the one hand, and between the reinforcing frame 8 and the plastics material frame 30 on the other hand, by surrounding / penetration / entanglement during overmolding. This makes it possible to permanently block the possibilities of relative displacements of the plastic parts with respect to the metal parts and to reinforce the cohesion of the assembly of heterogeneous materials. There are provided multiple holes 17, 18 of the peripheral flange 6b and the reinforcing frame 8, in particular on its third portion 8c. The distribution of the bores and their unit opening surface are determined to avoid the occurrence of visible shrinkage to the right of the bores of the sheet on external surfaces having an aesthetic role.

This FIG. 2 further illustrates an example of a joint plane 13 between the two half-shells not forming part of a continuous plane. In particular, protruding elements 19, made of plastic, of the rear part 4 are provided for insertion into the reinforcing frame 8. The assembly and fixing of the front 3 and rear 4 parts is ensured by fastening means such as screws and / or clips.

With reference to FIG. 3, an exemplary embodiment of the overmolding of the metal sheet and the reinforcement frame according to the invention is seen. There is a mold 20 of shape strictly including the plastic frame 30, the metal sheet 6 and the reinforcing frame 8. At startup, only the metal sheet 6 and the reinforcing frame 8 are arranged in the mold. The assembly is brought to a temperature of the order of 100 degrees, then the constituent plastic of the frame 30 is injected at about 200 degrees under a pressure of about 200 bars. FIG. 3 shows two joint planes 21 and 22 of the mold 20 allowing it to open during demolding. Referring to Figure 4, we see an alternative embodiment of the housing according to the invention. The metal foil consists only of a lip 31 defining the rim of a window through which the screen 9 is seen. In this case, the plastic frame 30 serves as a support on which the lip 31 is glued. After overmolding on the reinforcing frame 8, the frame 30 can be machined so as to produce a plane location on which the lip 31 is glued. This plane can, in another embodiment, be obtained directly during the operation of overmolding. Preferably, the gap between the lip 31 and the reinforcing frame 8 is partially or completely filled with plastic and constitutes said planar location. The lip 31 is a thin sheet with a thickness of less than 0.2 mm, preferably equal to 0.1 mm, which is bonded to an extremely rigid structure by virtue of the overmolding of the reinforcing frame 8.

Figure 5 is a simplified top view and off scale of a tablet according to the invention. We see that the screen 9 is framed by a thin lip of a beautiful finish 14a or 31, which lip is securely attached to a rigidified frame 30 through a reinforcing frame. The latter is visible in Figure 6 which is a sectional view at this reinforcing frame 8. The screen 9 is located inside the reinforcing frame, while the frame is securely attached to the reinforcing frame by overmolding.

The invention thus relies on the combined use of metal sheet and plastic to produce composite parts in the context of a manufacturing process by overmolding massive interpenetration of metal parts.

The invention makes it possible to combine with synergetic effects the best of the characteristics of the parts made of organic plastics or metals obtained by molding and the contributions of the metal in the form of sheet metal. The invention provides for close cooperation between the heterogeneous materials that are the plastic and the metal which provides exceptional characteristics especially in terms of material reduction for a given rigidity. The invention is based on overmoulding of the metal parts arranged to provide a great cohesion between the materials. Although the means that provide the results have nothing to do with each other, the invention has certain analogies with reinforced concrete. This analogy makes it possible to intuitively appreciate certain advantages of the invention. To achieve the goal of great cohesion between heterogeneous materials, the invention provides a large number of interpenetration points of the metal parts where the plastic material penetrates during overmolding.

The main advantages of the molded material in the context of use of the invention are the ease of obtaining complex shapes, functionalization capabilities of these forms inside the housing, for example to wedge or to fix sub internal assemblies such as a hard disk, a screen, one or more batteries, one or more printed circuits, etc. Another important advantage of the plastic material is its transparency with regard to radio waves which makes it possible to include antennas. Another advantage is the relatively low cost of this plastic material. The use of non-magnetic and / or non-ferrous alloys is compatible with certain types of antennas.

The contribution of metal in the field of portable electronic devices is particularly interesting to improve the quality perceived by the user, and contribute usefully to the shielding of electronics and, where appropriate, to the efficiency of antennas by forming large planes. mass.

The invention aims to capitalize the respective advantages of each material and to add those arising from the joint implementation according to the invention.

The presence of metal elements in the composite housing according to the invention is also advantageous for better dissipating the heat produced inside the apparatus. For some devices in which electronic components must be in contact with a heat sink, the addition of a low thermal resistance interface piece between the surface of the components concerned and a metal part of the composite package according to the invention makes it possible to perform the function at the lowest cost.

The advantages of the invention are also important in terms of aesthetic rendering and perception to touch. The casing resulting from its implementation of the method according to the invention makes it possible to obtain a perfect aesthetic line directly, particularly at the borders, in particular in the gaps and outcrops between the external metal surfaces and those made of plastic. Of course, the invention is not limited to the examples which have just been described and many adjustments can be made to these examples without departing from the scope of the invention.

Claims

An electronic device housing, comprising at least a front portion and a rear portion shaped to be joined to each other by defining an interior volume adapted to receive functional components of the apparatus, said functional components comprising at least a screen visible from the outside through a window; characterized in that at least the front portion comprises:

- A metal sheet disposed firmly on the frame and having a lip outside the housing, this lip covering a portion of the screen so as to form the rim of said window.

2. Housing according to claim 1, characterized in that the lip has a thickness less than or equal to 0.2mm.

3. Housing according to claim 1 or 2, characterized in that the lip has a thickness less than or equal to 0.1mm.

4. Housing according to any one of the preceding claims, characterized in that the lip constitutes a flat frame and the metal sheet further comprises a peripheral edge partially integrated by overmolding in the frame, the peripheral rim having a non-zero angle relative to in the plane frame.

5. Housing according to claim 4, characterized in that the lip and the frame are arranged substantially flush, especially coplanar, at the junction between the peripheral rim and the lip.

6. Housing according to claim 4 or 5, characterized in that the depth of penetration of the peripheral rim in the frame is less than or equal to 2mm.

7. Housing according to any one of claims 4 to 6, characterized in that the metal sheet has bores and / or notches located on the peripheral rim, traversed at least in part by plastic or injectable metal.

8. Housing according to any one of the preceding claims, characterized in that the metal sheet is bonded to the frame after overmolding the reinforcing frame.

9. Housing according to any one of the preceding claims, characterized in that it comprises a gap between a portion of the metal sheet and the reinforcing frame.

10. Housing according to claim 9, characterized in that it comprises an adhesive sheet between the metal sheet and the reinforcing frame to secure a portion of the metal sheet with the reinforcing frame.

11. Housing according to claim 9, characterized in that it comprises a spot weld in the interstice for securing a portion of the metal sheet with the reinforcing frame.

12. Housing according to any one of the preceding claims, characterized in that the reinforcing frame is shaped in the shape of "U" or "V", the closed side of the "U" or "V" being oriented towards the sheet metallic.

13. Housing according to any one of the preceding claims, characterized in that the reinforcing frame comprises bores and / or indentations traversed at least in part by plastic or injectable metal.

14. Housing according to any one of the preceding claims, characterized in that it is sized for a screen whose size is between 6.5 and 15 inches.

15. Housing according to any one of the preceding claims, characterized in that the front and rear portions comprise abutments and / or centering ribs shaped to ensure a joined assembly of their adjacent peripheral edges.

16. Housing according to any one of the preceding claims, characterized in that at least one antenna is disposed in the plastic frame, this antenna being connected to certain functional components of the electronic device.