Instrument pointer illumination apparatus

Abstract: An instrument pointer illuminating apparatus for illuminating instrument pointers includes a light conductive member (24) having a first shaft aperture (22) and an instrument face (28) disposed on a front surface of the light conductive member and having a second shaft aperture (26) therein. A pointer shaft (20) extends through the first and second shaft apertures beyond the front surface of the light conductive member and includes an instrument pointer (30) disposed on the pointer shaft. A light blocking hub cap (34) is mounted on the hub portion (43) of the instrument pointer and includes a centre portion (50) and a cylindrical wall portion (52) extending from the centre portion of the hub cap toward the instrument face where it terminates at a first end (54) below the instrument pointer. A light blocking baffle ring (36) is disposed on and extends away from the instrument face toward the instrument pointer and terminates at a second end at a point closer to the instrument pointer than the first end of the cylindrical wall portion. The resulting instrument pointer illuminating apparatus substantially reduces undesirable halos normally associated with illuminated instruments.

Description: The present invention relates to an apparatus for illuminating instrument pointers. More particularly, light is conducted through the pointers without creating a disturbing halo image on the instrument face. It is known to provide for illuminated pointers for instruments, as shown in Figure 1, in which pointers are illuminated by reflectively transmitting light into the pointer. In such instruments, a portion of the light emitted to illuminate the pointer is "lost" through reflections 10 which leak onto an instrument face 12, creating the appearance of a glowing halo on the instrument face. The halo reduces the clarity and readability of any markings on the instrument. It would be desirable to have an illuminated pointer for instruments capable of significantly reducing or eliminating this halo. JP 11 211513 A describes an illuminating device for a pointer mounted on a rotating shaft above an instrument face. A light guide plate has a reflecting surface to reflect incident light onto a light receiving part of the pointer. A light shielding cap is placed over the upper side of the pointer where it receives the incident light. A light shielding ring protrudes from the upper side of the instrument face to the inside of the pointer cap. JP 11 248493 describes an illuminating device for a pointer mounted on a rotating shaft. A colour tone conversion layer is formed at a light receiving part of the pointer. Blue light is introduced through a light guide to illuminate light transmitting parts of an instrument face but is converted by the conversion layer to white light upon entry to the pointer. The white light is finally emitted as a red colour at an indicating section of the pointer. According to the present invention, there is now provided an instrument pointer illuminating apparatus for illuminating instrument pointers comprising: a light conductive member having a first shaft aperture; an instrument face disposed on a front surface of said light conductive member and having a second shaft aperture; a pointer shaft extending through said first and second shaft apertures beyond said front surface of said light conductive member; an instrument pointer disposed on said pointer shaft and including a hub portion; and a light blocking hub cap mounted on said hub portion of said instrument pointer, said light blocking hub cap including a centre portion and a cylindrical wall portion extending from said centre portion of said hub cap toward said instrument face and terminating at a first end below said instrument pointer; characterised by; a light blocking baffle shield disposed on a bottom side of said instrument pointer and having a planar portion with a third shaft aperture for receiving said pointer shaft therethrough, said light blocking baffle shield extending radially outward to engage said cylindrical wall portion of said light blocking hub cap; and means to reduce light reflection in the form of; a light blocking baffle ring disposed on and extending away from said instrument face toward said instrument pointer and terminating at a second end at a point closer to said instrument pointer than said first end of said cylindrical wall portion; or a light blocking baffle wall disposed on and extending away from said instrument pointer toward said instrument face and terminating at a third end in close proximity to the instrument face. The present invention has an advantage that it substantially reduces the halo created on an instrument face as an undesired by-product of illuminating an instrument pointer. The present invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a sectional side view of an illuminated instrument pointer producing a halo image on an instrument face; Figure 2 is a sectional side view of one embodiment of an instrument pointer illuminating apparatus for illuminating an instrument pointer according to the present invention; Figure 3 is a sectional side view of another embodiment of an instrument pointer illuminating apparatus for illuminating an instrument pointer according to the present invention; Figure 4 is a sectional side view of another embodiment of an instrument pointer illuminating apparatus for illuminating an instrument pointer according to the present invention; Figure 5 is a plan view of an illuminated instrument pointer for use in an instrument pointer illuminating apparatus in accordance with the present invention; and Figure 6 is a sectional side view of another embodiment of an instrument pointer illuminating apparatus for illuminating an instrument pointer according to the present invention. Referring now to Figures 2 and 6, an apparatus for illuminating instrument pointers in accordance with the present invention is shown. The apparatus is provided with an enclosure 14 having a transparent viewing window 16, housing therein at least one instrument. The instrument includes a pointer driver 18 mounted within the enclosure 14 and having a pointer shaft 20 extending through a first aperture 22 in a light conductive member 24 and a second aperture 26 in an instrument face 28, which overlays the light conductive member 24. An instrument pointer 30, driven by the pointer driver 18 through the pointer shaft 20, is illuminated by light transmitted from a lamp 32 into the light conductive member 24 through a light collecting extension 25. It should be noted that the enclosure 14 could include numerous illuminated and non-illuminated instruments, such as are found in the instrument panel of a motor vehicle. The present invention eliminates or substantially reduces any visible halo by using individual or a combination of baffles together with a light blocking hub cap 34 positioned to block reflected light from reaching the instrument face 28. The baffles, which will be described in greater detail below include a light blocking baffle ring 36, a light blocking baffle wall 38, a light blocking baffle shield 40 and a light blocking cylindrical wall extension 42. To improve the readability of the specification, further reference to these features throughout this description will be without recitation of their "light blocking" nature, it being understood that they possess the physical characteristic of being relatively non-transparent. The light conductive member 24 is made of a transparent material such as polycarbonate. The light conductive member 24 includes the light collecting extension 25, which in the illustrated embodiment is merely an extension of the bottom surface 33 of the light conductive member 24. The light conductive member 24 also includes a light transmitting section 35 disposed on at least a portion of the periphery of the first aperture 22, preferably having a diameter smaller than that of the baffle wall 38. The light transmitting section 35 includes a bevelled surface 37 formed to reflect light toward the instrument pointer 30. Alternatively, while not shown, the pointer could be directly illuminated, such as by an LED aligned with the instrument pointer. The instrument face 28 may be constructed by bonding a mask onto an upper surface of the light conductive member 24, or, alternatively, the instrument face could be painted onto the upper surface of the light conductive member. Essentially the instrument face 28 includes areas where light transmission is substantially blocked and other areas where light transmission is allowed, thereby illuminating characters and various shapes to form dial faces and characters thereon. The instrument face 28 extends to the periphery of the light conductive member 24 to prevent light leakage at the joint of the enclosure 14 and the light conductive member 24. The instrument face 28 does not block the light transmitting section 35 of the light conductive member 24. The instrument face includes the second aperture 26, preferably having a diameter smaller than that of the baffle wall 38. Referring now to Figures 2, 5 and 6, the instrument pointer 30 includes a hub portion 43 mechanically interconnected, preferably in a press-fit manner, to the pointer driver 18 by the pointer shaft 20. The instrument pointer includes a light receiving portion 44 arranged to be above the light transmitting section 35 of the light conductive member 24, preferably throughout its range of motion, so as to provide consistent illumination of the instrument pointer. A bottom surface 46 of the needle portion 48 of the instrument pointer 30 is also covered with a light blocking mask 49, formed by printing, painting or bonding a light blocking material thereon, to prevent light from the instrument pointer from reflecting downward onto the instrument face 28. The hub cap 34 is snap-fit or bonded onto the hub portion 43. The hub cap 34 is constructed of a non-transparent, closed cylinder including a centre portion 50 and a cylindrical wall portion 52 extending downward from the centre portion 50 toward the instrument face 28 and terminating at a first end 54 (more distinctly visible in Figure 3), generally just below the bottom surface 46 of the needle portion 48 of the instrument pointer. As shown in Figure 2, the hub cap 34 includes the cylindrical wall extension 42 extending from the first end 54 further downward toward the instrument face and terminating at a fourth end 56. The baffle ring 36 is located on the instrument face 28 of light conductive member 24 and extends upwards towards the instrument pointer 30 a predetermined height to terminate at a second end 58, preferably falling above either the first or fourth ends of the hub cap 34. Depending on the diameter of the baffle ring, it may not form a complete circle, to prevent blocking light transmission between the light transmitting section 35 and the light receiving portion 44 of the instrument pointer. Preferably, however, the baffle ring 36 will be sized such that it will form a completely closed circumference, with the light transmitting section 35 and the light receiving portion 44 falling completely within the closed circumference. The baffle wall 38 extends downward from the bottom of the hub portion 43 of the instrument pointer 30 a predetermined height and terminates at a third end 60, preferably falling as close as possible to the instrument face or at least below the second end 58 of the baffle ring 36. Like the baffle ring, depending on the diameter of the baffle wall, it may not form a closed loop so as not to block light transmission between the light transmitting section 35 and the light receiving portion 44 of the instrument pointer. Additionally, the baffle wall may not form a circular shape, rather it could simply be two or more relatively planar baffle walls positioned to provide as much blockage of light reflection as is possible. Preferably, however, the baffle wall 36 will be sized such that it will form a completely closed circumference and fall within the area enclosed by the baffle ring 26. The baffle wall can be either a formation of the instrument pointer itself or a separate part bonded to the instrument pointer, in the case where the baffle shield is present, it can be an extension integrally formed therewith. It should also be recognised by those skilled in the art that it may be advantageous to use multiple concentric baffle walls to provide further halo reduction. The baffle shield 40 matches the bottom of the hub portion of the instrument pointer, generally planar, and extends radially outward to and engages in a secure and light sealing manner to the cylindrical wall portion of the hub cap. The baffle shield includes a third shaft aperture 64 for receiving the pointer shaft therethrough and also includes a light transmitting window 66 for conducting light into the light receiving portion 44 of the instrument pointer from the light transmitting section 35 of the light conductive member 24. In the simplest forms of illuminated instruments, light emitted from the lamp 32 enters the light conductive member, and reflects on the bevelled surface 37 of the light transmitting section 35 upward into the a light receiving portion 44 of the illuminated pointer. In the embodiment illustrated in Figure 2, the various baffles as well as their overlapping relationship with other baffles prevent light leakage outside of the hub cap area, thus preventing the undesirable image of a halo on the instrument face. Referring now to Figures 3, 4 and 6, alternative embodiments of the present invention are illustrated, all demonstrating significant reductions in the halo generated by reflections from the lamp 32. Figure 3, illustrates an embodiment having the second end of the baffle ring 36 extend upward to a height above the height of the first end 54 of the cylindrical wall portion 34 of the hub cap. Of course, if the cylindrical wall extension were integrally formed with the hub cap, the second end of the baffle ring 36 would only need to extend upward to a height above the height of the fourth end 56 (not shown). Figure 4 illustrates yet another embodiment of the present invention, wherein the baffle shield 40 and baffle wall 38 are implemented alone, with the third end 60 of the baffle wall extending downward to a position in close proximity with the instrument face. In this embodiment, it is preferred that the baffle wall be configured as a completely closed circumference, with the light transmitting section and the light receiving portion falling completely within this closed circumference to provide maximum reflection reduction. The foregoing description presents several embodiments of the present invention. Details of construction have been shown and described for purposes of illustration rather than limitation. For example, it should be recognised to those skilled in the art that illuminated instruments can be used in many applications beyond the instrument panel of a motor vehicle. In other applications, considered within the wording of the claims, it is common to find multiple pointers driven on a common instrument.

Claims: An instrument pointer illuminating apparatus for illuminating instrument pointers comprising: a light conductive member (24) having a first shaft aperture (22); an instrument face (28) disposed on a front surface of said light conductive member (24) and having a second shaft aperture (26); a pointer shaft (20) extending through said first and second shaft apertures (22,26) beyond said front surface of said light conductive member; an instrument pointer (30) disposed on said pointer shaft (20) and including a hub portion (43); and a light blocking hub cap (34) mounted on said hub portion (43) of said instrument pointer (30), said light blocking hub cap (34) including a centre portion (50) and a cylindrical wall portion (52) extending from said centre portion (50) of said hub cap toward said instrument face and terminating at a first end (54) below said instrument pointer (30); characterised by ; a light blocking baffle shield (40) disposed on a bottom side of said instrument pointer (30) and having planar portion with a third shaft aperture (64) for receiving said pointer shaft (20) therethrough, said light blocking baffle shield (40) extending radially outward to engage said cylindrical wall portion (52) of said light blocking hub cap (34); and means to reduce light reflection in the form of; a light blocking baffle ring (36) disposed on and extending away from said instrument face toward said instrument pointer (30) and terminating at a second end (58) at a point closer to said instrument pointer (30) than said first end (54) of said cylindrical wall portion (52); or a light blocking baffle wall (38) disposed on and extending away from said instrument pointer (30) toward said instrument face (28) and terminating at a third end (60) in close proximity to the instrument face (28). An instrument pointer illuminating apparatus according to Claim 1, wherein said means to reduce light reflection comprises the said light blocking baffle ring (36), the light blocking baffle ring (36) being circular and fitting within said cylindrical wall portion (52) of said light blocking hub cap (34). An instrument pointer illuminating apparatus according to Claim 1, wherein said means to reduce light reflection comprises the said light blocking baffle ring (36) and the apparatus further comprises a light transmitting section of said light conductive member (24) disposed within said light blocking baffle ring (36). An instrument pointer illuminating apparatus according to Claim 1, wherein said instrument pointer (30) is light conductive such that light from said light conductive member (24) illuminates said instrument pointer (30). An instrument pointer illuminating apparatus according to Claim 1, wherein the means to reduce light reflection comprises the said light blocking baffle wall (38), the light conducting baffle wall (38) further comprising a cylindrical wall extension integral with and extending from said first end of said cylindrical wall portion (52) to a fourth end (56), said fourth end (56) being closer to said instrument face (28) than said third end (60). An instrument pointer illuminating apparatus according to Claim 5, wherein the means to reduce light reflection comprises the said light blocking baffle wall (38), the light blocking baffle wall (38) extending from the light blocking baffle shield (40) disposed on the bottom side of said instrument pointer (30). An instrument pointer illuminating apparatus according to Claim 1, wherein the means to reduce light reflection comprises the said light blocking baffle wall (38) and the light blocking baffle wall (38) constitutes one of at least two of such light blocking baffle walls.

Inventors: KALASHNIKOV SERGEI, KALASHNIKOV, SERGEI
Applicants: VISTEON GLOBAL TECH INC, VISTEON GLOBAL TECHNOLOGIES, INC.
Application year: 2000
Main classification: G01D11
IPC codes: G01D11, G01D13