GB2562475A - Display module and manufacturing method thereof - Google Patents
Display module and manufacturing method thereof Download PDFInfo
- Publication number
- GB2562475A GB2562475A GB1707656.3A GB201707656A GB2562475A GB 2562475 A GB2562475 A GB 2562475A GB 201707656 A GB201707656 A GB 201707656A GB 2562475 A GB2562475 A GB 2562475A
- Authority
- GB
- United Kingdom
- Prior art keywords
- light guide
- light
- display
- display module
- back surface
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0033—Means for improving the coupling-out of light from the light guide
- G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
- G02B6/0045—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it by shaping at least a portion of the light guide
- G02B6/0046—Tapered light guide, e.g. wedge-shaped light guide
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0065—Manufacturing aspects; Material aspects
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0081—Mechanical or electrical aspects of the light guide and light source in the lighting device peculiar to the adaptation to planar light guides, e.g. concerning packaging
- G02B6/0083—Details of electrical connections of light sources to drivers, circuit boards, or the like
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0081—Mechanical or electrical aspects of the light guide and light source in the lighting device peculiar to the adaptation to planar light guides, e.g. concerning packaging
- G02B6/0086—Positioning aspects
- G02B6/0088—Positioning aspects of the light guide or other optical sheets in the package
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/1336—Illuminating devices
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Nonlinear Science (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mathematical Physics (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Planar Illumination Modules (AREA)
Abstract
A display module (10, figure 2) that comprises a display panel 14 such as a liquid crystal display (LCD) panel or a thin-film- transistor (TFT) LCD panel and a backlight unit 12 that comprises a light guide 18 configured to conduct light emitted by a light source 22 towards the back surface of the display panel; characterized in that said light guide 18 is made of transparent material moulded over the back surface 20 of the display panel 14. A method of manufacture which includes overmolding of a display assembly with a light guide structure on its back side is also disclosed. At least one reflective element may be arranged on a back surface of the light guide and the light source may be over molded with the light guide.
Description
(54) Title of the Invention: Display module and manufacturing method thereof Abstract Title: Display module with a light guide moulded over the back surface of the display panel (57) A display module (10, figure 2) that comprises a display panel 14 such as a liquid crystal display (LCD) panel or a thin-film- transistor (TFT) LCD panel and a backlight unit 12 that comprises a light guide 18 configured to conduct light emitted by a light source 22 towards the back surface of the display panel; characterized in that said light guide 18 is made of transparent material moulded over the back surface 20 of the display panel 14. A method of manufacture which includes overmolding of a display assembly with a light guide structure on its back side is also disclosed. At least one reflective element may be arranged on a back surface of the light guide and the light source may be over molded with the light guide.
Fig.l
1/1
Fig.l
Fig.2
Display module and manufacturing method thereof
TECHNICAL FIELD
The present invention relates to display modules including backlight units, preferably for use in automotive applications.
BACKGROUND OF THE INVENTION
Backlight units of today’s Thin-Film-Transistor (TFT) or Liquid Crystal Display (LCD) display modules are using direct or indirect illumination.
Current direct display backlight units are made from light sources like electrical bulbs, Light Emitting Diodes (LED) or gas tubes (e.g. Cold Cathode Fluorescent Lamps) which are located behind a display panel (TFT or LCD). The light source is sending their light directly to the display which is located in line of sight of the display. The housing behind the display panel is typically covered with reflective material, which reflects most of the light which is not all directed to the display. This structure is called “light box” and ensures a suitable efficiency of the display backlight unit. The light box can be molded from reflective material or can be made from sheet based material which will be folded inside the display compartment or can be made by painting of a reflective paint on a non-reflective material.
Lenses might be used on top of the light sources in order to spread the light on top of the light sources. This leads to a better illumination intensity evenness on the display and allows to reduce the distance in between the light source and the display. These lenses are made currently from optically clear plastic material or silicone and are discrete devices (molded in a discrete process). They are typically mounted by screws, clips or are glued to the structure supporting the light source such as the Printed Circuit Board (PCB).
Current indirect display backlight units are also made from light sources like bulbs, LEDs or CCFL tubes, but they are not located in the direct line of sight of the display (TFT or LCD). The light source is sending its light into a light guide device which is changing the direction of the light and directing it to the display panel. All light guide devices are made from optically clear plastic material or silicone and are currently discrete devices. The housing around the light guide and the light sources is typically covered by a reflective material. The light guide together with the light sources and the covering reflective material are typically mounted in a cover which is made from sheet metal. This structure holds the light sources in place in order to optimize the efficiency of the display backlight unit.
Existing backlight units require a relatively complex assembly process since multiple discrete parts need to be assembled in small areas.
The invention will propose a solution to make the assembly simpler, cheaper, while providing a very efficient backlighting of the LCD display.
SUMMARY OF THE INVENTION
The present invention describes a display module comprising a backlight unit where the light guide is made by overmolding on the back of a display panel by using a combination of optically clear and highly reflecting silicone or plastic materials which have a sufficient temperature and chemical behavior regarding their melting and/or curing temperature and/or chemical mixture in order to not damage the display, the laminated films on the display and the mounted electronic or electric components on the light source assembly.
The light sources might be mounted first to the display on a printed circuit board and/or metal assembly in order to over mold them together with the display panel. It is also possible to install a separate light source unit perpendicular or in direction to the display on a printed circuit board and/or metal assembly which will be assembled to the display panel after the molding process. All light sources will emit their light in perpendicular or in parallel direction to the display panel into the light guide structure. The structure of the light guide will be designed in a way that the light will be guided towards the display with the maximum transfer efficiency and illumination intensity evenness.
By overmolding of a display assembly with a light guide structure on its back side, which is guiding the light from light sources towards the display, it is possible to (a) improve the illumination intensity evenness and to use a lower number of light sources compared to backlight units with discrete light guides, (b) improve the light transfer from the light sources to the display in order to increase the illumination efficiency, (c) direct the light from the light source towards the display in order to influence the optical viewing angle on top of the display, (d) decrease the structural complexity of a display backlight unit by reducing the number of optical components (e.g. sparing diffusor/BEF/DBEF films) and (e) save cost of the backlight unit by an optimized manufacturing process.
The overmolded light guide might contain typical optical structures like concave/convex lenses, Fresnel lenses or complex optical structures in the pm and/or nm range.
The present invention proposes a display module and a manufacturing method thereof according to the attached set of claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is now described by way of example with reference to the accompanying drawings in which:
- Figure 1 is an axial cross section showing a display module with indirect backlighting according to a first embodiment of the present invention;
- Figure 2 is an axial cross section showing a display module with direct backlighting according to a second embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the following description, parts which are identical or similar may be designated by the same reference.
A first embodiment of the present invention relating to a display module 10 with an indirect backlight unit 12 is represented on figure 1. Figure 1 shows a LCD display module 10 comprising a display panel 14 mounted on a housing 16. The backlight unit 12 comprises a light guide 18 molded over the back surface 20 of the display panel 14.
The backlight unit 12 comprises a light source 22 such as a light emitting diode or a light tube which emits light through a receiving surface 24 of the light guide 18 in order to redirect light towards the back surface 20 for backlighting the display panel 14.
The light source 22 is assembled to the top surface 26 of a printed circuit board 28 in order to be connected to an electronic circuit suitable to control the light source 22 and the entire display module 10.
Advantageously, the light source 22 can be molded with the light guide 18 before being assembled to the printed circuit board 28. Thus the display panel 14 together with the light guide 18 and the light source 22 constitute a discrete module which can be more easily manipulated and which is thinner.
Alternatively, the light guide 18 can be molded such as forming a suitable receiving surface 24 substantially complementary to the outer shape of the light emitting portion of the light source 22 in order to be assembled to the light guide 18 after the molding process.
In the example represented on figure 1, the printed circuit board 28 is mounted on a bottom wall 30 of the housing 14.
According to the present embodiment the light guide 18 has the shape of a panel with a thickness diminishing progressively from the light source side towards the opposite free end. The shape of the light guide 18 is optimized to ensure optimal redirection of the light entering into the light guide 18 through the receiving surface 24 towards the emitting surface 32 facing the back surface 20 of the display panel 14.
Advantageously, a reflective element 34 such as a reflective layer is arranged on the bottom surface of the light guide 18 to reflect the light inside the light guide 18 towards the emitting surface 32. The reflective layer can be made of reflective plastic material, reflective silicon, or reflective paint.
Alternatively, the reflective element 24 can be made of optical structures forming prisms or facets to redirect the light. Such optical structures can be made by molding.
Advantageously, the display panel 12 includes on its top and bottom surfaces some polarization layers 36, 38.
With reference to figure 2, a second embodiment of the present invention will be described wherein the backlight unit 12 is of direct type since the light sources 22 are facing the back surface 20 of the display panel 14. All light sources 22 are typically distributed over the whole area of the display panel 14 in order to allow an even distribution of light over the whole back surface 20 of the display panel 14.
The light sources 22 can be multiple light emitting diodes and are completely covered by the transparent material constituting the light guide 18.
As for the first embodiment, the light sources 22 are preferably over molded with the light guide 18 before being mounted and/or connected to the printed circuit board 28 but can be alternatively assembled to the light guide 18 after having been mounted on the printed circuit board 28. In that last case the light 5 guide 18 is molded with some cavities on its bottom surface to allow insertion of the light sources 22 and optimal transmission of light into the light guide 18.
A method of manufacturing a display module 10 according to the first or second embodiment comprises the steps of:
- providing a display panel 14,
- molding a light guide 18 made of transparent material over the back surface of the display panel 14 together with the light source 24.
List of references:
10: display module
12: back light unit
- 14: display panel
16: housing
18: light guide
20: back surface
- 22: light source
- 24: receiving surface
- 26: top surface
28: printed circuit board
30: bottom wall
32: emitting surface
- 34: reflective element
- 36, 38: polarization layers
Claims (12)
1. A display module comprising:
- a display panel such as a liquid crystal display (LCD) panel or a thin-filmtransistor (TFT) LCD panel,
- a backlight unit comprising a light guide configured to conduct light emitted by a light source in the direction of said display, characterized in that said light guide is made of transparent material molded over the back surface of the display panel.
2. A display module according to claim 1, characterized in that said light source is over molded with the light guide.
3. A display module according to any one of claims 1 or 2, characterized in that at least one reflective element is arranged on a back surface of the light guide.
4. A display module according to claim 3, characterized in that the reflective element comprises a reflective layer made of reflective plastic material, or reflective silicon, or reflective paint which is over molded with the light guide.
5. A display module according to claim 3 or 4, characterized in that the reflective element comprises optical reflective structures molded on the back surface of the light guide.
6. A display module according to any one of the preceding claims, characterized in that the light guide is made of silicon or plastic material.
7. A display module according to any one of the preceding claims, characterized in that the light source is a light emitting diode.
8. A display module according to any one of the preceding claims, characterized in that it comprises a plurality of light sources.
9. A display module according to claim 8, characterized in that the plurality of light sources is distributed substantially homogenously over the back surface of the display panel.
5 10. A method of manufacturing a display module according to any one of claims 1 to 9, comprising the steps of:
- providing a display panel,
- molding a light guide made of transparent material over the back surface of the display panel,
10 - providing at least one light source.
11. A method according to claim 10 wherein the light guide is molded over the display panel together with the light source.
15
12. A method according to claim 10 or 11 comprising the additional step of depositing a layer of reflective material onto the back surface of the light guide.
Intellectual
Property Office
Application No: GB1707656.3 Examiner: Mrs Rachel Morgans
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1707656.3A GB2562475A (en) | 2017-05-12 | 2017-05-12 | Display module and manufacturing method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1707656.3A GB2562475A (en) | 2017-05-12 | 2017-05-12 | Display module and manufacturing method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB201707656D0 GB201707656D0 (en) | 2017-06-28 |
| GB2562475A true GB2562475A (en) | 2018-11-21 |
Family
ID=59201450
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1707656.3A Withdrawn GB2562475A (en) | 2017-05-12 | 2017-05-12 | Display module and manufacturing method thereof |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2562475A (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1185074A (en) * | 1997-09-05 | 1999-03-30 | Yazaki Corp | Display device and manufacturing method thereof |
| JP2004133167A (en) * | 2002-10-10 | 2004-04-30 | Matsushita Electric Ind Co Ltd | Reflective display device |
| WO2015118813A1 (en) * | 2014-02-10 | 2015-08-13 | シャープ株式会社 | Lcd device |
-
2017
- 2017-05-12 GB GB1707656.3A patent/GB2562475A/en not_active Withdrawn
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1185074A (en) * | 1997-09-05 | 1999-03-30 | Yazaki Corp | Display device and manufacturing method thereof |
| JP2004133167A (en) * | 2002-10-10 | 2004-04-30 | Matsushita Electric Ind Co Ltd | Reflective display device |
| WO2015118813A1 (en) * | 2014-02-10 | 2015-08-13 | シャープ株式会社 | Lcd device |
Also Published As
| Publication number | Publication date |
|---|---|
| GB201707656D0 (en) | 2017-06-28 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |