Illumination – Sound equipment illuminator
Reexamination Certificate
1999-04-15
2001-09-11
Sember, Thomas M. (Department: 2875)
Illumination
Sound equipment illuminator
C362S234000
Reexamination Certificate
active
06286972
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a button carrier and display backlight for an electronic device, for example a button carrier and display backlight for use with an audio device such as a motor vehicle cassette radio unit.
2. Disclosure Information
Electronic devices often have a combination of user operable buttons and a display. One known way of providing such buttons is to have a plastics material button carrier, for example a moulded piece of plastic that is held in place behind a front panel or bezel. The buttons, or areas adjacent each button, may be backlit, for example being moulded in a clear plastic on which opaque or translucent paint has been applied. The backlight then is projected through the translucent paint, for example to display words, symbols or to indicate if the button is on or off.
It is often necessary to provide more than one button carrier, for example if the buttons are arranged in areas separated by the display. In one arrangement known from a motor vehicle cassette radio, a display is held on a display carrier on which light emitting diodes (LEDs) are mounted for backlighting the display; and two separate button carriers hold buttons on either side of the display carrier. Each carrier has its own printed circuit board (PCB) on which LEDs for backlighting the display or buttons.
The display may be a liquid crystal display, backlit with a convenient source of light such as an array of LEDs. A transmissive diffuser, such as frosted clear plastic material, is sometimes provided so that the light is more evenly distributed across the display. The display LEDs may be mounted on a printed circuit board, on which the display and optionally a diffuser may be clipped or otherwise held.
Therefore, it is generally necessary for a number of carriers, optical components and PCBs to be fixed, for example by means of screws, to the inner surface of the cassette radio bezel, which is in turn clipped to the cassette radio chassis. The need to have a number of separate components with associated manufacturing steps adds to the cost of the electronic device.
It would be desireable to provide a more convenient carrier arrangement in which a button portion and a display portion may be backlit.
SUMMARY OF THE INVENTION
According to the present invention, there is provided a button and display carrier, comprising a button portion and a display portion integrally moulded in a translucent plastics material, the button portion having at least one backlight arranged to shine through the translucent material, and the display portion having at least one backlight arranged to illuminate a backlight area of the translucent material, to provide a diffuse back illumination for a display, characterized in that the diffuse back illumination is provided by light incident upon and surface-scattered from the backlight area.
Preferably the composition of the translucent material is substantially uniform in both the button and display portions.
The display may be any type of display suitable for back illumination, such as a liquid crystal display.
The surface-scattered light will be mainly from light reflected and back-scattered from the surface of the backlight area. But because the material is translucent, a significant proportion of the light will penetrate the surface, for example at least half of the total incident light will not be reflected from the surface. Therefore, the term surface-scattered light also includes light back-scattered from the bulk of the translucent material, especially from the bulk closest the surface of the backlight area.
Such surface scattering provides a relatively efficient means of spreading the light from the light source, with minimum absorption and stray reflection by the translucent material, particularly if the light upon the surface of the backlight area is incident at a shallow angle over substantially most or all the area. The term shallow angle is used herein to refer to an angle within 45° of the surface at a point on the backlight area, and preferably less than about 30°. The efficiency of illumination becomes more important for larger area displays owing to the need otherwise to employ a large number of light sources to provide sufficient illumination.
Therefore, at least one backlight of the display portion may be disposed to one side of the backlight area, and illuminates the surface of the backlight area at a shallow angle. Preferably the display portion has a linear array of backlights disposed along an edge of the backlight area, the surface of the backlight area being concave in a plane perpendicular to the axis of the linear array. The concave shape may have an essentially parabolic shape, so that the illumination intensity of each unit area of the backlight area is relatively constant.
Optionally, there may be more than one button portion and/or more than one display portion. In a preferred embodiment of the invention, there are two button portions either side of a middle display portion.
The button portion may have an opaque surface coating over part of the translucent material, so that the button portion is backlit through the uncoated part. The uncoated parts may therefore display information regarding the function or status of the button, for example whether or not it has been activated by the user.
In a preferred embodiment of the invention, the button portion has at least one button integrally moulded with the carrier. For example, each button may have a linking hinge formed from integrally moulded translucent material. The linking hinge may be an integrally moulded flexure means allowing the button to flex inwards to the bezel as a user presses the button.
In order to reduce manufacturing cost, it is advantageous if the at least one backlight for the button portion and the at least one backlight for the display portion are mounted on a common circuit board held to the carrier, for example by clips or screws.
REFERENCES:
patent: 4536625 (1985-08-01), Bebie
patent: 4625263 (1986-11-01), Strohmeier
patent: 4634818 (1987-01-01), Hayes-Pankhurst
patent: 4638131 (1987-01-01), Kidd et al.
patent: 4659183 (1987-04-01), Suzawa
patent: 5012054 (1991-04-01), Rada et al.
patent: 5127057 (1992-06-01), Chapmen
patent: 5166815 (1992-11-01), Elderfield
patent: 5235636 (1993-08-01), Takagi
patent: 5255162 (1993-10-01), Kawamoto
patent: 5311656 (1994-05-01), Eldershaw
patent: 5397867 (1995-03-01), Demeo
patent: 5537300 (1996-07-01), Kraines
patent: 5596343 (1997-01-01), Snider
patent: 5655826 (1997-08-01), Kouno
patent: 5727866 (1998-03-01), Kraines
patent: 5920150 (1999-07-01), Crary
patent: 5940015 (1999-08-01), Thornton
patent: 3806042 A1 (1988-02-01), None
patent: 0 644 564 A1 (1995-03-01), None
patent: 0 644 564 B1 (1997-11-01), None
patent: 2 690 589 (1993-10-01), None
patent: 2 181 283 A (1987-04-01), None
Garnham Adrian
Shepherd Mark Robert
Sawhney Hargobind S.
Sember Thomas M.
Shelton Larry I.
Visteon Global Technologies Inc.
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