CN108345144B

CN108345144B - Display device and electronic apparatus equipped with the same

Info

Publication number: CN108345144B
Application number: CN201810072643.5A
Authority: CN
Inventors: D.瓦格纳; M.黑泽; J.赫茨; E.巴达罗夫
Original assignee: Festo SE and Co KG
Current assignee: Festo SE and Co KG
Priority date: 2017-01-25
Filing date: 2018-01-25
Publication date: 2023-03-28
Anticipated expiration: 2038-01-25
Also published as: DE102017201125A1; DE102017201125B4; CN108345144A

Abstract

The invention relates to a display device having an at least partially light-permeable display screen (12) and a backlight (26) arranged on the rear side of the display screen (12), wherein the backlight is arranged on the rear side of the display screen. The backlight device (26) has a light source device (34) and a light distribution device (42) arranged behind the display screen (12). The light distribution device (42) comprises a light guide plate (27) which acts in a light-conducting and light-dispersing manner and into which light for the backlighting can be coupled laterally and on the rear side of which a light-impermeable shielding reflective wall (28) extends, which optically shields a circuit carrier (33) which is equipped with a light source device (34).

Description

Display device and electronic apparatus equipped with the same

Technical Field

The invention relates to a display device having an at least partially light-permeable display screen and a backlight associated with the display screen, wherein the backlight has a light source device, which is designed to generate light, having at least one light source, and a light distribution device, which is arranged on the rear side of the display screen, wherein the light that can be generated by the light source device can be coupled into at least one lateral edge section of a light guide plate of the light distribution device, which light guide plate acts as a light diffuser and can exit from the light guide plate as scattered light at a front side facing the display screen.

The invention further relates to an electronic device which is equipped with at least one functional unit and a display device constructed in the aforementioned sense for displaying information relating to the functional unit.

Background

The light-permeable display screen is usually designed as a liquid crystal display, that is to say as a so-called LCD (liquid crystal display) and requires a backlight which is as homogeneous as possible in order to ensure good readability. A display device of the aforementioned type is known from DE 20 2007 010 985 U1, which is equipped with a backlight device with a large-area light distribution device arranged behind an LDC, which is formed by a rectangular light guide plate into which light that can be generated by means of a light source device formed by a plurality of LEDs can be coupled in at a plurality of lateral edge sections by means of light incoupling means. The light incoupling means have one or more obliquely running reflection surfaces arranged next to the light guide plate, which are responsible for the entry of light into the light guide plate with an intensity that is distributed as uniformly as possible.

In this connection, the applicant has also already known internally in a manner that cannot be ascertained in the printed literature that display devices have also been proposed in which the light source device extends directly behind the light guide plate, which however requires a relatively large structural height of the display device to achieve uniform light coupling into the large rear side of the light guide plate.

Disclosure of Invention

The object on which the invention is based is to create a compactly constructed display device which, in the case of compact dimensions, achieves a uniform backlighting of its display screen. An electronic apparatus equipped with such a display device should also be provided.

In order to achieve this object, it is provided in the case of a display device of the type mentioned at the outset that the light distribution device has a light-impermeable shielding reflective wall arranged on the rear side of the light guide plate, through which light coupled into the light guide plate can be reflected in the direction of the display screen, wherein a circuit mount which is equipped with the light source device and is optically shielded by the shielding reflective wall of the light guide plate extends behind the light distribution device.

The display device according to the invention comprises a light distribution device arranged behind an at least partially light-permeable display screen, which has a light guide plate and a light-impermeable, shielding, reflecting wall arranged at the back side at the light guide plate. In operation of the display device, light coupled into the lateral edge sections of the light guide plate is diffused through the light guide plate and exits the light guide plate as scattered light with uniform distribution at the front side opposite the shielding reflective walls in order to illuminate the front-facing display screen. The lateral coupling-in of light into the light guide plate enables the placement of the light source device at least one lateral end region of the light distribution device associated with a lateral edge section of the light guide plate, so that the region behind the light distribution device can be used for further purposes. In particular, it is possible that a circuit carrier, which extends behind the light distribution device and carries the light source device, is provided on its front side facing the light distribution device with a substrate, which forms an electronic circuit. Such substrates, for example containing a microcontroller and/or an LCD driver module, can negatively affect the light power of the display device without shadowing the reflective walls, since they usually have an absorptively acting dark hue and can moreover cause an undesired reflection of light. The shielding reflective wall excludes such inaccessibility, since it prevents light from exiting the light guide plate at the back side and instead reflects impinging light forward in the direction of the display screen based on its reflective characteristics. The light coupled into the light guide plate can thus be guided very point by point at the edge side to the display screen with high intensity, wherein the divergent character of the light guide plate causes the light exiting from the light distribution device towards the display screen to appear as scattered light with a noticeable uniformity, so that the display screen is qualitatively high for the visual impression of the viewer. The lateral light coupling allows the overall height of the display device, measured from the rear side to the front side, to be kept very small, even if an intermediate space between the shielding reflective wall and the circuit mount is used for accommodating electronic components arranged on the circuit mount. Thus, the electronic device equipped with the display device can be realized in an extremely flat structural manner.

Advantageous developments of the invention are apparent from the dependent claims.

This structural design of the display device enables uniform light to be provided with high intensity even with a low light power of the light source device. If the light source arrangement is constructed using LEDs, that is to say light-emitting diodes, a smaller number of LEDs is already sufficient to obtain a very intensified backlight of the display screen. Losses are avoided by shielding the reflective walls and a large part of the incoupled light can be made to exit at the front side of the light guide plate for illuminating the display screen. A more satisfactory backlight intensity has been obtained with a light source arrangement having only two LEDs.

The at least partially light permeable display screen is preferably a segmented LCD. The display screen preferably has a plate-like structure and extends in particular in a plane parallel to the plane of extent of the circuit carrier. The circuit carrier is in particular embodied as a printed circuit board provided with conductor tracks, that is to say as a printed circuit board. However, it can also be realized, for example, as an MID component (MID = molded interconnect), that is to say as an injection molded circuit carrier. In this case, particular advantages result in terms of flexible shaping.

Preferably, the light source devices are divided into a plurality of light source units each equipped with at least one light source, which are distributed annularly around the light guide plate on the edge side, such that they are associated with different lateral edge sections of the light guide plate.

It has proven to be particularly advantageous if the light guide plate is provided with an at least approximately rectangular plan view, wherein the light source device has exactly two light source units which are arranged in the region of two mutually opposite lateral edge sections of the light guide plate. The light guide plate has, for example, the form of an elongated rectangle, wherein a light source unit, in particular having at least one and preferably exactly one LED, is associated with each of the two narrow lateral edge sections.

The light guide plate is arranged at a height distance with respect to the circuit carrier based on the presence of the shielding reflective wall. In order to nevertheless achieve optimum light incoupling, it is advantageous if the backlight has light incoupling means which direct the light emitted by the light source device to at least one lateral edge section of the light guide plate in a targeted manner. In an advantageous manner, in combination with such light incoupling means, LEDs realized as SMD components can be mounted at the front side of the circuit carrier facing the display screen, which have their light exit area at the Top side opposite the circuit carrier, wherein such LEDs are also referred to as Top LEDs (Top-LEDs).

Preferably, the light incoupling means has at least one reflective wall arranged next to a lateral edge section of the light guide plate, which, on the basis of its dependency from the light incoupling means, for better differentiation shall be referred to as an incoupling reflective wall and can deflect and conduct light emitted by the light source means by reflection to the associated lateral edge section of the light guide plate. In particular, it is thereby possible to deflect the light emitted from the LEDs in the direction of the front side of the display device to the side by a deflection angle of, for example, 90 °, that is to say preferably in the region which lies at the same height as the adjacent lateral edge section of the light guide plate.

It is particularly advantageous if the light incoupling means are realized by one or more light incoupling units, which each follow the design of the light box. Such a light box represents a box-shaped housing having on its inside the feature of reflecting light, into which housing, from the underside, at least one light source fixed at the circuit carrier projects. The light box furthermore has light exit apertures for the light to be coupled in facing the lateral edge sections of the adjacent light guide plates, wherein the light emitted by the at least one light source, in passing through the light box, undergoes at least one reflection by a coupling-in reflective wall formed by a section of the light box wall. The light exit opening is preferably designed as a slit, wherein the slit extends in the longitudinal direction, in particular in a main plane of extension of the light guide plate.

A particularly advantageous construction of the light distribution means provides that the shielding reflective wall is an integral part of the reflector body specific to the light guide plate. In the simplest case, the reflector body is constituted only by the shielding reflective wall. The reflector body is, however, preferably designed such that it has further reflector body components, which for example define a recess open towards the front side of the display device, into which the light guide plate is inserted in a preferably releasable manner. The reflector body and the light guide plate can be produced separately from one another by means of a simple, controllable production technique and must be arranged on one another only with the required relationship in the case of the assembly of the display device.

Thereby, the light guide plate and the shielding reflective wall form a light distribution means implemented as an assembly. This embodiment is preferably an alternative embodiment in which the shielding reflective walls are formed by a reflective film which is applied to the rear side of the light guide plate and is glued, for example.

The light guide plate, which is constructed separately with respect to the shading reflective walls, preferably at least approximately matches the contour of the shading reflective walls on its rear side facing the shading reflective walls. The two parts preferably bear directly against one another. Preferably, the back side of the light guide plate is configured complementary to the front side shielding the reflection of the reflective wall.

When the backlight device is further equipped with at least one incoupling reflective wall, it is advantageous if this is an integral part of the reflector body which is specific and identical to the light guide plate, as is the shading reflective wall. This enables particularly cost-effective production, for example in injection molding processes.

Preferably, the reflector body is constructed in one piece. The shielding reflector wall and, if appropriate, at least one coupling-in reflector wall are formed here by a section of the one-piece reflector body. The reflector body is in particular made of a white plastic material, so that it does not absorb light and has the best possible reflection characteristics. Alternatively, plastic materials of other colors can also be used, which are preferably white-coated in the region for reflection.

The one-piece reflector body is produced in particular as an injection-molded plastic body.

The circuit carrier is expediently equipped at its front side with a plurality of electrically conductive contact surfaces which are in electrically conductive connection with further contact surfaces arranged at the display screen. In this way, the display function of the display screen can be controlled by the electrical signals provided by the circuit mount. A particularly simple and reliable electrically conductive connection between the contact surfaces on both sides is achieved in particular by means of at least one rubber-elastic connecting piece having a conductive rubber structure. Preferably, the reflector body is penetrated in its vertical direction by one or more receiving wells, in each of which a connecting piece of this kind is releasably received, wherein at least one receiving well is situated such that the connecting piece situated therein extends laterally in the vertical direction past the light guide plate.

The circuit carrier is expediently equipped at its front side facing the display screen not only with each light source of the light source device but additionally with an electronics component assembly having at least one electronics component. The electronics component assembly can be provided for electrically operating a light source device for emitting light and/or for operating a display screen for displaying information. In addition or alternatively, an electronic component assembly can be provided in order to handle any type of functional unit provided with electrical and/or electronic components, which is electrically connected with the display screen with the electronic component assembly being coupled in between, in such a way that the display screen can display information about the operation of the functional unit. The electronic component assembly preferably has at least one microcontroller which contains at least one electronic processor and preferably also further electronic peripheral structures. In addition or as an alternative to the microcontroller, the electronics component assembly may also contain, inter alia, an LCD driver module. Since the light-impermeable shielding reflection wall optically shields the electronic component assembly toward the light guide plate that conducts and disperses light, the functionality of the light guide plate is not impaired by its presence.

Preferably, at least one lateral edge section of the light guide plate, which is provided for coupling light into the light guide plate, is associated with a lateral end region of the light distribution device, wherein the shielding reflective wall has at least one inclined reflective wall section, which extends from the lateral end region of the light distribution device with an associated inclined course beyond at least one partial region of the circuit mount. The inclined reflective wall section is designed in particular such that it is also removed from the circuit mount in the direction of the display screen onwards as the distance from the lateral end region of the light distribution device increases. This aspect has the positive effect that light components reflected at the shielding reflective walls at a larger distance with respect to the lateral end regions of the light distribution means exit at the front side of the light guide plate with at least substantially the same intensity as light components reflected near the regions of the shielding reflective walls located at the lateral end regions of the light distribution means. Another advantage is that an intermediate space, which varies in its height, is formed between the circuit mount and the shielding reflector wall, which can be used advantageously for mounting components of the electronic component assembly.

The inclined course of at least one inclined reflective wall section may be linear or also non-linear, wherein the non-linear course is in particular a curved course, the concave side of which faces the light guide plate.

The shielding counter-shield can be formed by a single inclined reflective wall section which extends in a continuous inclined direction beyond the circuit mount. Such a design is then particularly recommended when the backlight is configured for coupling light into only one individual lateral edge section of the light guide plate. In a further advantageous embodiment, the backlight device is equipped for coupling in light with two mutually opposite lateral edge sections of the light guide plate, which are each associated with one of two mutually opposite lateral end regions of the light distribution device. In this case, the shading reflective wall preferably has a roof-like, in particular saddle-roof-like, outer shape and has two inclined reflective wall sections which are to extend toward one another starting from one of the two mutually opposite lateral end regions of the light distribution device, which transition into one another in a first region having the greatest distance from the circuit mount, wherein this first region defines the greatest height of the intermediate space formed between the circuit mount and the shading reflective wall.

As mentioned above, the light guide plate is preferably adapted to the shape of the shading reflector wall on its rear side. If the shielding reflective wall has at least one inclined reflective wall section, the light guide plate suitably also has at least one inclined rear section at its rear side extending along the inclined reflective wall section. The light exit surface of the slanted rear section, which is located on the front side facing the display screen with respect to the light guide plate, preferably has a slanted profile, which extends parallel to the main plane of extent of the display screen.

The display device may advantageously be an integral part of the electronic apparatus. The object on which the invention is based is also achieved by an electronic device which is equipped via at least one functional unit and a display device for displaying information about the functional unit, wherein the display device is constructed in the manner shown above, and wherein an electronic circuit which is constructed for operating the functional unit is present on the circuit mount. The electronic circuit has, in particular, an electronic component assembly arranged at the circuit carrier at the front side facing the display screen, which does not have to satisfy special requirements with regard to its optical absorption capacity and reflection properties, since it is shielded by the shielding reflective wall for coupling in light into the light guide plate.

In a preferred embodiment, the electronic device is designed as a sensor, with which one or more application-relevant state variables can be detected. The detected measured values and/or the information generated thereby can be visualized by means of a display screen. In a preferred embodiment, the sensor is a flow sensor, the functional unit of which can detect the flow rate of a flowable medium, for example pressurized air. However, the sensor may also be, for example, a pressure sensor or a position sensor, wherein this list is understood as non-decisive.

Drawings

The invention will be explained in detail below with reference to the attached drawing figures, in which:

fig. 1 shows a preferred embodiment of the display device according to the invention in combination with an equally advantageous embodiment of the electronic device, preferably a flow sensor,

fig. 2 shows a front view of the components diagrammatically shown in fig. 1 in a state in which the housing of the display device is removed, in the direction of the line of sight according to the arrow II in fig. 1 and 3, and does not show functional units combined or combinable with the display device,

figure 3 shows an exploded view of the main components of the display device,

figure 4 shows a side view of the assembly of figures 2 and 3 in a line of sight according to arrow IV,

in fig. 5 a longitudinal section through the display device according to the section line V-V of fig. 2 and 6 is shown, an

Fig. 6 shows a further longitudinal section of the display device according to arrows VI-VI of fig. 4 and 5 in a section plane perpendicular with respect to the section plane of fig. 6.

Detailed Description

Fig. 1 shows diagrammatically an electronic device 1 which has a functional unit 2 and is equipped with a display device 3 which is suitable for displaying information relating to the functional unit continuously or in a called-up manner. According to an example, the functional unit 2 is a detection unit 2a, which can detect one or more state quantities, in particular physical state quantities. The detection unit 2a is designed for detecting the flow rate of a flowing fluid, wherein the flowing fluid can be a gaseous or liquid medium, in particular compressed air or a process liquid. The electronic device 1 is in this respect a sensor 1a, in particular a flow sensor.

In order to be able to detect the state quantity of the flowing fluid, the functional unit 2 contains at least two fluid connections 4, through which fluid connections 4 the fluid to be detected can flow in or out. The fluid connection 4 is arranged on a sensor housing 5 of the functional unit 2, through which a fluid subjected to a detection measure can flow and in which a detection means 6, which is indicated by a dashed line, is present and which can detect a state variable of interest.

In order to visualize and/or evaluate the measured values detected by the detection means 6 and/or to process them, the electronic device 1 is equipped with an electronic circuit 8, which is constructed using an electronic component assembly 7, which is suitably integrated into the display device 3. The electronic circuit 8 is electrically connected to the detection means 6 within the electronic device 1 in a manner not illustrated in any further detail.

Furthermore, there is an electrical connection between the electronic circuitry 8 of the display device 3 and the display screen 12 which is constructed to be at least partially light-permeable. In the following, for better differentiation of the display device 3, also referred to as an electronic display device, this is illustrated in fig. 3 by the dotted arrow 13 and is preferably realized by connecting a plurality of rubber-elastic connecting pieces 14 having a conductive rubber structure. Each of these rubber-elastic connecting blocks contains, in a known manner, an alternating series connection of electrically conductive and electrically insulating rubber sections, wherein the electrically conductive rubber sections are designated by dashed lines 15 in fig. 3 in the case of the connecting block 14.

The display device 3 has a vertical axis 16, which extends between a front side 17 and a back side 18 of the display device 3. In the rest of the use orientation known from the figures, the front side 17 points upwards. In this connection, the front side and/or the rear side are subsequently referenced in conjunction with the display device 3 or individual components of the entire electronic device 1, whereby the same orientation is to be understood as in the case of the front side 17 and the rear side 18.

The vertical axis 16 suitably also defines the vertical axis of the entire electronic device 1.

The display device 3 has a longitudinal axis 23 perpendicular to the vertical axis 16 and a transverse axis 24 perpendicular not only to the vertical axis 16 but also to the longitudinal axis 23. The dimensions of the display device 3 are exemplary greater in the axial direction of the longitudinal axis 23 than in the axial direction of the transverse axis 24. The display device 3 preferably has an elongated rectangular plan view, viewed in a top view in the axial direction of the vertical axis 16, which is also referred to below as vertical. However, the proportions can also be designed differently from this. The longitudinal axis 23 and the transverse axis 24 together define a main plane 22 of the display device 3 perpendicular to the vertical axis 16.

The display 12 is preferably a flat display. The display screen 12 is in particular embodied in the form of a plate, the plate plane thereof being oriented parallel to the main plane 22. The display 12 has a plurality of display elements 25, which in the case of this embodiment are formed by individual segments of a segmented LCD, wherein "LCD" stands for "liquid crystal display", which may also be referred to as liquid crystal display.

The light transmission of the display screen 12 is selectively changeable irrespective of the electrical manipulation of the display screen 12. Which is particularly suitable for existing display elements. In this way, the display 12 can display information relating to the operating state of the associated functional unit 2, in particular measured values or other data generated from the measured values, for example. In the case of this embodiment, the display screen 12 is used for playing the flow value, which can be generated in the case of the connection detection device 6 and the electronic circuit 8.

Depending in particular on the functionality of the electronic circuit 8, the display 12 can also perform further visualizations, such as the display of values that can be entered by means of the keyboard 29, for example, within a parameterized framework. A simple run ready display may also be visualized, for example using the display screen 12.

The display screen 12 defines a front side 17 of the display device 3. On the rear side of the display screen 12 in the axial direction of the vertical axis 16, there is a backlight 26 of the display device 3, by means of which the display screen 12 can be backlit, that is to say can be lit from its rear side, in order to enable, in the case of viewing from the front side 17, the readout of information visualized by the display element 25 on the basis of the contrast caused by the different light transmissibility.

The backlight device 26 comprises in particular in a preferred embodiment a light guide plate 27, a reflector body 32 with a shielding reflective wall 28 and a circuit carrier 33, which carries a light source device 34.

The reflector body 32 is incorporated between the light guide plate 27 and the circuit carrying part 33. The shielding reflective wall 28 extends between the light guide plate 27 and the circuit carrier 33.

The circuit carrier 33 has a carrier surface 35 on its front side facing the display screen 12 in the vertical direction 16, where the light source device 34 is fixed. In particular, at this support surface 35, the power supply support 33 is also provided with the electronic circuit 8, which has already been mentioned above and which is composed of the electrical component assembly 7, which has also been mentioned above, and in particular also a plurality of conductor tracks 36, which are indicated schematically by dashed lines. The electronics component assembly 7 comprises at least one and preferably a plurality of electronics components 37 which are electrically conductively connected to one another in a suitable manner by means of conductor tracks 36. At this conductor track 36 there is preferably also coupled a light source device 34, so that it can be supplied with electrical energy, so that it generates and emits light for backlighting of the display screen 12.

The light source arrangement 34 contains at least one and preferably a plurality of individual light sources 38. Preferably, at least one and suitably each Light source 38 is an LED (Light-Emitting-Diode), i.e. a Light-Emitting Diode. LEDs can cause high intensity point-by-point light with less energy consumption.

The light guide plate 27 and the reflector body 32 together form a light distribution device 42 which gives the light emitted by the light source device 34 uniformly distributed as scattered light at the front side of the light guide plate 27 facing the display screen 12, the surface thereof facing the front of the display screen 12 therefore also being referred to below as light exit surface 43. The scattered light causes the display panel 12 to emit light or backlight from its back side.

The light generated by the light source arrangement 34 is coupled into the light guide plate 27 and is distributed by the light guide plate 27, on the basis of its respective construction, in a conducting, diverging and scattering manner. The light is coupled in exemplarily at two lateral edge sections 44 of the light guide plate 27, which are opposite to each other in the axial direction of the longitudinal axis 23 and which expediently have a rectangular plan view. The light guide plate 27 is disposed such that its main extension plane extends parallel to the main plane 22 of the display device 3.

The light exit face 43 extends parallel to the main plane 22 between two lateral edge sections 44. The light guide plate 27 has a back face 45 facing the shielding reflective wall 28 at a back side facing away from the display screen 12 in the vertical direction 16.

The reflector body 32 is preferably a one-piece component. It is composed in particular of a plastic material, wherein it is expediently made of a white plastic material in order to avoid undesired light absorption. The reflector body 32 is preferably an injection molded plastic part.

The shielding reflective wall 28 is an integral part of the reflector body 32. The shielding reflective wall 28 preferably forms a bottom surface of a recess 46 of the reflector body 32 which is open toward the front side 17, into which the light guide plate 27 is inserted in the vertical direction 16 from the front side 17. The light guide plate 27 rests with its rear face 45 against the shielding reflector wall 28.

The reflector body 32 is preferably designed in the region of the recess 46 in a pot-shaped manner.

The light distribution device 43 has two lateral end regions 47 which are opposite to one another in the axial direction of the longitudinal axis 23. Each of the two lateral end regions 47 is associated with one of the two lateral edge sections 44 of the light guide plate 47. The shielding reflective wall 28 extends between two lateral end regions 47, wherein it completely covers the light guide plate 27 at its rear side. The shielding reflective wall 28 is configured to be light-impermeable, so that light coupled into the light guide plate 27 cannot reach the area located behind the shielding reflective wall 28 in the vertical direction 16, where the circuit carrier 33 extends.

The reflector body 32 is placed at the bearing surface 35 of the circuit carrier part 33, preferably in a releasable manner. Here, it is shaped such that the shielding reflective wall 28 extends beyond the circuit carrier 33 by a distance measured in the vertical direction 16. Thereby, the shielding reflective wall 28 limits the intermediate space 48, which serves as a receiving cavity 48a for the electronic component assembly 7 arranged at the bearing surface 35 of the circuit carrier 33, together with the circuit carrier 33.

The circuit carrier 33 is preferably embodied in the form of a plate, the plate plane thereof extending parallel to the main plane 22.

By shielding the reflective wall 28, the circuit carrier 33 and particularly also the electronic component assembly 7 arranged at the front side thereof is optically shielded by the light guide plate 27. Furthermore, the front side of the shielding reflection wall 28 facing the display screen 12 is configured as a reflection surface 52, which can reflect impinging light of the light source device 34, which was previously coupled into the light guide plate 27, in the direction towards the light exit surface 43 and thus also in the direction towards the display screen 12. An increase in the light intensity of the scattered light leaving at the light exit face 43 is thereby obtained.

In the case of a light-permeable light guide plate 27, the coupled-in light is dispersed at corresponding dispersing structures (not otherwise illustrated) of the light guide plate 27. The diverging structures may be located inside the light guide plate 27 and/or at the light exit face 43, depending on the construction of the light guide plate 27. In fig. 5, possible paths of the scattered and reflected light are schematically indicated by dotted lines with arrows.

The reflector body 32 preferably has two longitudinal side walls 53 which are arranged opposite one another at a distance in the axial direction of the transverse axis 24 and which enclose the intermediate space 48, more precisely the receiving space 48a, on the longitudinal sides and preferably extend as far as the circuit mount 33, where they preferably rest against the mounting surface 35 thereof.

In the case of the illustrated preferred embodiment, the light source device 34 is divided into two light source units 54 which are arranged at a distance from one another. Each of the two light source units 54 contains at least one light source 38, wherein each light source unit 54 is provided with, by way of example, exactly one light source 38. Each light source unit 54 is located in the region of one of the two mutually opposite lateral edge sections 44 of the light guide plate 27. Each light source unit 54 is expediently coupled to the light guide plate 27 at the lateral edge section 44 associated therewith, viewed in a vertical direction 16 in a front view. In other words, the light guiding unit 54 is arranged in the axial extension of the light distribution means 42 in the case of this embodiment.

The individual light sources 38 are preferably positioned laterally and medially with respect to the light guide plate 27.

The two light source units 54 are expediently each located in a region which is connected to the intermediate space 48 in the axial direction of the longitudinal axis 23. In order to prevent undesired light falling into the intermediate space 48, the reflector body 32 is expediently separated from the associated light source unit 54 at each of the two mutually opposite end regions of the shading reflective wall 28 by a separating wall 55 extending in the vertical direction 16. The circuit mount 33 on the rear side of the reflector body 32 expediently bears both against the longitudinal side wall 53 and against the two separating walls 55. In this way, the intermediate space 48 is enclosed in an annular manner by the reflector body 32 and the components of the circuit mount 33.

The light source 38 is expediently arranged directly on the bearing surface 35 of the circuit bearing part 33. This results in a height difference of the edge sections 44 associated with the light guide plate 27, which is arranged at a height distance from the circuit mount 33 in order to form the intermediate space 48. Nevertheless, in order to enable the best possible coupling-in of the generated light into the light guide plate 27, the light distribution means 42 are suitably equipped with light incoupling means 56 which cause a suitable light incoupling.

The light incoupling means 56 comprise for each light source unit 54 its own light incoupling unit 57. The backlight 26 of the illustrated embodiment is correspondingly equipped with two light incoupling units 57, each associated with one of the two lateral end regions 47 of the light distribution device 42, where one of the light source units 54 is also present. Each light incoupling unit 57 has a reflective wall arranged in the optical path of the light emitted by the light source unit 54, which for better distinction shall be referred to as incoupling reflective wall 58 and which is arranged next to each of the two lateral edge sections 44 in the axial extension of the light guide plate 27. The incoupling reflective wall 58 has a reflective surface 62 facing the associated light source unit 54, the light given by the light source unit 54 being reflected by this reflective surface 62 in a direction towards the adjacent lateral edge section 44 of the light guide plate 27.

The reflection surface 62 is expediently arranged at a distance in the axial direction of the vertical axis 16 in front of the associated light incoupling unit 57.

Each light source 38 for forming a light source unit 54 is preferably mounted at the carrier surface 35 according to this embodiment such that its light exit area 63 faces away from the circuit carrier part 33 and points in a direction towards the front side 17. In this connection, a so-called top LED is preferably used as the light source, the light exit region 63 of which, in the intended mounted state of the LED, is located at the top side of the LED facing away from the circuit mount 33. The emitted light thus leaves the respective light source unit 54 approximately in the direction of the front side 17, wherein the incoupling reflective walls 58 are disposed at an inclination of this type toward the light exit region 63, i.e. the light impinging on the associated reflective surface 62 is reflected laterally, i.e. transversely to the vertical axis 16, in the direction of the adjacent lateral edge section 44 of the light guide plate 27.

As is apparent from the above embodiments, the shielding reflective wall 28 is preferably an integral part of the reflector body 32, which is a component specific to the light guide plate 27. In the same way, the at least one incoupling reflective wall 58 is preferably also an integral component of the reflector body 32, which corresponds to the illustrated embodiment. The reflector body 32 is suitably a one-piece member that includes not only the shielding reflective walls 28, but also each of the incoupling reflective walls 58.

Each light incoupling unit 57 is preferably equipped with a housing-like structure, called a light box 64, which delimits an inner cavity, called a light emission cavity 65, which has a rear box hole 66 that opens out towards the rear side of the reflector body 32, which is covered by the circuit carrier 33 that abuts on the rear side at the reflector body 32. The light source unit 54 is fixed to the circuit mount 33 at a section bridging the rear cartridge opening 66 and projects into the light emission chamber 65.

The light box 64 has a light box wall 67 bounding the light emission cavity 65, which is partly formed by the incoupling reflective wall 58. In the light box wall 67, furthermore, light exit apertures 68 are formed at the side of the light box 64 facing the light guide plate 27, preferably arranged at the same height as the adjacent lateral edge sections 44 of the light guide plate 27. Which is located in the optical path of the light reflected at the reflecting surface 62 of the light source unit 54 coupled into the reflecting wall 58.

Thereby, the light emitted by the at least one light source 38 of the light source unit 54 is reflected in the interior of the light emission cavity 65 from the incoupling reflective wall 58 in the direction towards the light exit aperture 68 and passes directly from the light exit aperture 68 into the light guide plate 27, the lateral edge sections 44 of which are arranged directly in the region of the light exit aperture 68.

Light is coupled into the light guide plate 27 at the lateral edge sections 44, in particular at the lateral faces 49 of the light guide plate 27 oriented transversely with respect to the vertical axis 16.

Light is coupled into the light guide plate 27 by two light coupling-in units 57 from two mutually opposite lateral edge sections 44. The light exiting at the light exit face 43, which backlights the display panel 12, is thus composed of two light portions, which are each generated by one of the two light source units 54. The two light portions may at least partially overlap, with the weakening of the light intensity with increasing distance from the lateral edge section 44 resulting in the two light portions being divided in an away manner approximately into two light exit face portions, which transition into one another in the axial direction of the longitudinal axis 23. A symmetrical light path is preferably provided such that the two light portions exit at two light exit face sections of the light exit face 43, which each occupy approximately half the length of the light exit face 43.

In particular, a particularly uniform visualization of the scattered light leaving at the light exit surface 43 results when the shielding reflector wall 28 is designed such that it extends, starting from one of the two lateral end regions 47 of the light distribution device 42, obliquely in the direction of the opposing lateral end region 47, more precisely such that it, with increasing distance from the lateral end region 47 of the circuit mount 33, seeks its way forward in the direction of the display screen 12. The further the wall section of the shielding reflective wall 28 is from the lateral end region 47, the further it is spaced from the circuit carrier 33. Since this preferably applies to the longitudinal extent away from the two lateral end regions 47, a roof-like, in particular saddle-roof-like, design of the shading reflective wall 28 is preferably obtained with two inclined reflective wall sections 69, which each extend from one of the two lateral end regions 47 toward one another and are thereby removed simultaneously from the circuit mount 33, wherein they merge into one another in a transition region, referred to as the first region 73, which defines the maximum height distance from the circuit mount 33 and thus also the maximum height of the intermediate space 48, more precisely of the receiving space 48a.

In principle, the two reflector wall sections 69 can have a straight course. However, it has proven to be particularly advantageous for the two reflective wall sections 69 to have an at least slightly arched shape, wherein the concave region faces the light guide plate 27.

In particular, the section of the receiving space 48a associated with the first region 73 is suitable, due to its proportionally greater height, for receiving at least one electronic component 37 of a comparatively large design size, which in this embodiment is used for mounting the microcontroller 37a of the electronic circuit 8. Alternatively or in addition to the microcontroller 47a, there may be electronic components 37, which are LCD driver modules.

Preferably, the light guide plate 27 is shaped at its rear face 45 such that it matches the course of the reflecting face 52 defined by the shielding reflecting wall 28. The contour of the rear face 45 of the light guide plate 27 is preferably at least approximately complementary to the shielding reflector wall 28, so that it can bear against the shielding reflector wall 28 over a large area from the front side. Thus, the shielding reflective walls 28 may define an adjacent confinement layer of the light guide plate 27 that causes retro-reflection from impinging light into the interior of the light guide plate 27 without disturbing effects.

Exemplarily, the light guide plate 27 is profiled on its rear side in such a way that its rear side 45 approaches the light exit area 43 with increasing distance from the two lateral edge sections 44 and thus the thickness of the light guide plate 27 measured in the vertical direction 16 decreases from the two lateral edge sections 44 up to the intermediate region 74 associated with the first region 73.

In the case of an embodiment that is not illustrated, light incoupling at only a single lateral edge section 44 of the light guide plate 27 is achieved, wherein the shading reflective wall 28 is removed continuously from the circuit mount 33 over the entire length of the light guide plate 27 starting from a lateral end region 47 of the light distribution device 42 associated with this lateral edge section 44.

The display device 3 expediently has a cover cap 75 which is light-permeable in the region of the display screen 12 and which accommodates the display screen 12, the light distribution means 42 and the circuit mount 33 with the light source means 34. The cover cap 75 is placed on the aforementioned components from the front side 17 and, in the case of the electronic device 1, is expediently fastened, in particular in a loose manner, to the functional unit 2 in the region of its open rear side.

The display device 3 preferably comprises a plurality of the above-described further rubber-elastic connecting pieces 14, which are each expediently inserted into a receiving well 76 which passes through the reflector body 32 in the vertical direction 16. Each coupling piece 14 is mounted and clamped at the longitudinal side at the light guide plate 27 in this way. In the reflector body 32, a total of four receiving wells 76, each equipped with a connecting piece 14, are formed, which are each placed in pairs in the vicinity of one of the two lateral end regions 47 of the light distribution device 42.

Each connecting block 14 bears with its two end faces, which are opposite to one another in the vertical direction 16, on the one hand against a contact face 77 of the electronic circuit 8 and, on the other hand, against a further contact face, which is not illustrated in any further figures, and which is formed on the rear side at the display screen 12, in order to obtain the electrical connection which has already been described between the electronic circuit 8 and the display screen 12.

Claims

1. Display device with an at least partially light-permeable display screen (12) and a backlight device (26) associated with the display screen (12), wherein the backlight device (26) has a light source device (34) with at least one light source (38) which is designed to generate light, and a light distribution device (42) which is arranged on the rear side of the display screen (12), wherein light which can be generated by the light source device (34) can be coupled into at least one lateral edge section (44) of a light guide plate (27) of the light distribution device (42) which acts in a light-conducting and light-diverging manner and can leave as scattered light from the light guide plate (27) at a front side facing the display screen (12), wherein the light guide plate (27) is provided for coupling light into lateral edge sections (44) of the light guide plate (27) in association with lateral end regions (47) of the light distribution device (42), and wherein the light distribution device (42) has a light-impermeable shading reflective wall (28) which is arranged on the rear side of the light guide plate (27), wherein the light distribution device (27) can be coupled into the light guide plate (27) by reflection by the light-reflecting wall (28) and wherein the light-shielding device (34) is provided with light-reflecting light-shielding means (34), the circuit carrier part (33) carries, in addition to the light source device (34), at least one electronic component assembly (7) with an electronic component (37) beyond which the shielding reflective wall (28) extends,

it is characterized in that the preparation method is characterized in that,

the circuit carrier part (33) carries the electronic component assembly (7) at a carrier surface (35) at its front side facing the display screen (12), and

the shielding reflector wall (28) has at least one inclined reflector wall section (69) which extends from a lateral end region (47) of the light distribution device (42) over at least one partial region of the circuit mount (33), wherein this region is removed from the circuit mount (33) further forward with increasing distance from the lateral end region (47) of the light distribution device (42) in the direction of the display screen (12) in such a way that an intermediate space (48) varying in its height exists between the circuit mount (33) and the shielding reflector wall (28) and forms a receiving space (48 a) for electronic component assemblies (7) arranged at the mounting face (35) of the circuit mount (33).

2. Display device according to claim 1, characterised in that at least one of the light sources (38) is an LED (light emitting diode) and/or the display screen (12) is a segmented LCD (liquid crystal display).

3. The display device as claimed in claim 1 or 2, characterised in that the light source device (34) has a plurality of light source units (54) each containing at least one light source (38), which are associated with different lateral edge sections (44) of the light guide plate (27).

4. The display device according to claim 3, wherein the light guide plate (27) has an at least approximately rectangular plan view, wherein the light source device (34) has two light source units (54) which are associated with two mutually opposite lateral edge sections (44) of the light guide plate (27).

5. A display device as claimed in claim 1 or 2, characterized in that the backlight device (26) has at least one light incoupling means (56) associated with a lateral edge section (44) of the light guide plate (27) configured for incoupling light generated by the light source means (34) into the at least one lateral edge section (44) of the light guide plate (27).

6. A display device as claimed in claim 5, characterized in that the light incoupling means (56) have at least one incoupling reflective wall (58) arranged beside a lateral edge section (44) of the light guide plate (27), by means of which light emitted by the light source means (34) can be reflected in the direction of the associated lateral edge section (44) of the light guide plate (27).

7. A display device as claimed in claim 6, characterized in that the light incoupling means (56) have at least one light incoupling unit (57) arranged beside a lateral edge section (44) of the light guide plate (27), which has a light box (64) into which at least one light source (38) of the light source arrangement (34) fixed at the circuit carrier (33) projects, wherein the light box (64) has a light-impermeable box wall (67) formed in part by the incoupling reflective wall (58) and, at the side facing the light guide plate (27), a suitably slit-shaped light exit aperture (68) for the light to be incoupled into the light guide plate (27).

8. A display device as claimed in claim 6 or 7, characterized in that a light source arrangement (34) at a front side of the circuit carrier (33) facing the display screen (12) is arranged at the circuit carrier (33), wherein at least one light source (38) of the light source arrangement (34) has its light exit region (63) at its side facing away from the circuit carrier (33), and the incoupling reflective wall (58) extends over the light source arrangement (34) in an oblique course such that light emitted at the light exit region (63) is reflected laterally in the direction of an adjacent lateral edge section (44) of the light guide plate (27).

9. A display device as claimed in claim 1 or 2, characterized in that the shielding reflective wall (28) is an integral part of a reflector body (32) specific to the light guide plate (27).

10. A display device as claimed in claim 9, characterised in that the light guide plate (27) is embedded in the reflector body (32) from the side of the display screen (12).

11. A display device as claimed in claim 9, characterized in that the light-guide plate (27) has, at its front side, a light-exit face (43) facing the display screen (12) extending parallel to the main extension plane of the display screen (12) and, at its rear side, at least substantially matching the contour of the shielding reflective wall (28).

12. A display device as claimed in claim 5, characterized in that the light incoupling means (56) have at least one incoupling reflective wall (58) arranged beside a lateral edge section (44) of the light guide plate (27), by means of which light emitted by the light source means (34) can be reflected in a direction towards the associated lateral edge section (44) of the light guide plate (27), wherein at least one incoupling reflective wall (58) is an integral part of a reflector body (32) specific to the light guide plate (27).

13. A display device as claimed in claim 6, characterized in that the light incoupling means (56) have at least one light incoupling unit (57) arranged beside a lateral edge section (44) of the light guide plate (27), which has a light box (64) into which at least one light source (38) of the light source arrangement (34) fixed at the circuit carrier (33) projects, wherein the light box (64) has a light-impermeable box wall (67) formed in part by the incoupling reflective wall (58) and, at the side facing the light guide plate (27), a suitably slit-shaped light exit aperture (68) for the light to be incoupled into the light guide plate (27), wherein at least one incoupling reflective wall (58) is a constituent part of a reflector body (32) specific to the light guide plate (27).

14. A display device as claimed in claim 6 or 7, characterized in that a light source arrangement (34) at a front side of the circuit carrier (33) facing the display screen (12) is arranged at the circuit carrier (33), wherein at least one light source (38) of the light source arrangement (34) has its light exit region (63) at its side facing away from the circuit carrier (33), and the incoupling reflective walls (58) extend over the light source arrangement (34) in an oblique course in such a way that light emitted at the light exit region (63) is reflected laterally in the direction of an adjacent lateral edge section (44) of the light guide plate (27), wherein at least one incoupling reflective wall (58) is an integral part of a reflector body (32) specific to the light guide plate (27).

15. A display device as claimed in claim 9, characterised in that the reflector body (32) is constructed in one piece.

16. A display device as claimed in claim 15, characterised in that the reflector body (32) consists of a white or white coated light-impermeable plastic material.

17. A display device as claimed in claim 9, characterized in that the reflector body (32) is penetrated in its vertical direction (16) by at least one receiving well (76), in which a rubber-elastic connecting piece (14) with a conductive rubber structure is received, which connects the circuit mount (33) in an electrically conductive manner to the display screen (12), which extends laterally past the light guide plate (27).

18. Display device according to claim 1 or 2, characterized in that at least one electronic component (37) of the electronic component assembly (7) is formed by a microcontroller (37 a) and/or an LCD driver module.

19. The display device as claimed in claim 1 or 2, characterized in that the shielding reflective wall (28) is designed roof-like and has two inclined reflective wall sections (69) which extend towards one another starting from two mutually opposite lateral end regions (47) of the light distribution device (42) and which merge into one another in a first region (73) which defines the maximum height of an intermediate space (48) formed between the circuit mount (33) and the shielding reflective wall (28).

20. An electronic device with at least one functional unit (2) and a display device (3) for displaying information relating to the functional unit (2), characterized in that the display device (3) is constructed according to one of claims 1 to 19, wherein an electronic circuit (8) configured for operating the functional unit (2) is present on the circuit carrier (33).

21. The electronic device according to claim 20, characterized in that it is configured as a sensor (1 a).

22. The electronic device of claim 21, wherein the electronic device is configured as a flow sensor.