Pointer illuminating structure in measuring instrument

A pointer illuminating structure in a measuring instrument. A pointer of the measuring instrument is of a generally elongated structure and transparent. At an intermediate portion thereof, a light section is provided to extend substantially prependicularly to the generally elongated structure to form a T shape. The pointer has a flat upper surface and lower surfaces extending from about both side of the light inducing section. A reflective material is applied to the lower surfaces. Beneath the upper surface and above levels of the lower surface, cavities laterally extend to open sideways. Said cavities are defined by reflective surfaces. In alternative form, said elongated pointer is formed with a truncated conical portion at the light inducing section. Said truncated conical portion has a truncated conical reflective surface. The reflective material is applied to the side surfaces instead of the lower surface thereof.

BACKGROUND OF THE INVENTION 
The present invention relates to a pointer illuminating structure in a 
measuring instrument. 
Heretofore, a pointer illuminating structure has been demanded for 
improving the visuality of a measuring instrument when used during the 
night or for some reason concerned with design. 
As conventional pointer illuminating structures, there are such devices as 
shown in FIGS. 1 to 3, of which FIGS. 1 and 3 are perspective views of 
different conventional pointer illuminating structures and FIG. 2 is a 
sectional view of the structure of FIG. 1 as mounted to a measuring 
instrument. 
In FIG. 1, the numeral 6 denotes a pointer having a fore end portion 10 and 
a rear end portion 12, with a pointer cap 5 being fitted over an 
intermediate portion between the fore end portion 10 and the rear end 
portion 12 to cover that portion of the pointer 6. The numeral 7 denotes a 
pointer support shaft. 
Operation of the conventional structure of FIG. 1 will now be described 
with reference to FIG. 2. The numeral 2 denotes a dial plate of measuring 
instrument (not shown). Light is radiated diretly from a light source (not 
shown) to a photoconductive plate 4 which is attached to the back of the 
dial plate 2. The radiated light is incident upon the circumference of a 
central light receiving portion 7 which is opposed to the photoconductive 
plate 4, then this incident light is reflected as indicated with arrows in 
FIG. 2 by a conical reflective surface 34 formed in the central light 
receiving portion and reaches the fore and rear end portions 10 and 12 of 
the pointer 6 to illuminate those portions. 
In the structure of FIG. 3, the pointer 6 has only the fore end portion 10, 
not having the rear end portion 12, but the operation is the same as 
above. 
In those conventional devices having such constructions and functions, 
however, since the pointer cap 5 for the prevention of light leak is sure 
to be fitted over the pointer 6, the luminous portion of the pointer 6 is 
scissioned by the pointer cap 5, thus making it impossible to illuminate 
the entirety of the pointer 6. That is, the visuality in nighttime use is 
low, and also in point of design, there are restrictions. 
SUMMARY OF THE INVENTION 
It is the object of the present invention to provide an improved pointer 
illuminating structure capable of overcoming the above-mentioned drawbacks 
of the conventional devices and improving the visuality in nighttime use 
by illuminating the entirety of a pointer as an integral body, and having 
a good design. 
In order to achieve the above-mentioned object there is provided a pointer 
illuminating structure in a measuring instrument in which a pointer itself 
is illuminated by conducting light to the interior of the pointer, said 
pointer illuminating device including the pointer and a cap, said pointer 
comprising an upper transmissive colored portion, a lower reflective 
colored portion and a transparent portion disposed therebetween, said 
transparent portion being provided with a central reflecting portion 
having a plurality of sideways opened, hollow, curved reflective surfaces, 
and said cap covering, and said cap covering said central reflecting 
portion sideways and not covering the upper surface of the pointer.

DETAILED DESCRIPTION OF THE EMBODIMENTS 
The present invention will be described concretely hereinunder with 
reference to the drawings. 
In FIG. 4, the numeral 14 denotes an elongated pointer body composed of an 
upper transmissive colored portion 16, lower reflective colored portions 
18, 24 and a transparent portion 20 formed of a transparent resin between 
those upper and lower colored portions, the coloring being effected by 
two-color molding coating, or any other suitable method. These component 
portions are formed by insert molding or press-fit molding integrally with 
a pointer support shaft 22 which is used for connecting the pointer to the 
measuring instrument intreior (not shown). A more detailed explanation 
will now be made with reference to FIG. 5. Said transparent portion 20 of 
the pointer body 14 has a light inducing section 21 at an intermediate 
portion thereof. Said light inducing section 21 extends substantially 
perpendicularly to the generally elongated structure to form a T shape. 
Said transparent portion 20 has a substantially flat upper surface and 
lower surfaces extending from both sides of said light inducing section 
21. The lower reflective colored portion 24, which is formed at the rear 
end of the pointer, may be differently shaped to keep weight balance of 
the entirety of the pointer 14. The upper transmissive colored portion 16 
is applied to said flat upper surface of the transparent portion 20 and 
comprises a fore end part 26 for pointing to a scale mark on a dial plate 
(see 40 in FIG. 6) and a rear end part 28 having a design effect. Said 
lower reflective colored portions 18 and 24 are applied to said lower 
surfaces of the transparent portions 20. 
Further, in order to conduct refracted and reflected light rays of the 
introduced light to the upper fore end part 26, upper rear end part 28 and 
central upper surface 30 of the pointer effectively and uniformly, there 
is provided a central reflecting portion 32 at the central part of the 
pointer (above the transparent portion 20 overlying the pointer support 
shaft 22). 
A pair of divided pointer caps 36 and 37 are for covering sideways the 
other portions than the printer portion to be illuminated including the 
upper surface 30 to intercept light from the central reflecting portion 
32. The pointer caps 36 and 37, formed of a suitably colored resin or a 
light non-transmissive light metal such as an aluminum plate, are attached 
to both side faces of the pointer 14 by welding, fitting or any other 
suitable method. 
Operation of the device shown in FIG. 4 will now be described with 
reference to FIG. 6. Light from a light source (not shown) passes as 
indicated with arrows through a photoconductive plate 42 mounted on the 
back of a dial plate 40 of the measuring instrument, then is reflected in 
a vertical direction by a lower conical light introducing portion 44 of 
the pointer 14 and introduced to the central reflecting portion 32. Of 
importance in this connection is that the central reflecting portion 32 is 
formed with reflective surfaces 46 and 48 defining cavities laterally 
extending beneath said flat upper surface and above levels of said lower 
surfaces of the transparent portions 20 to open sideways. 
The reflective surface 48 reflects light to the upper fore end part 26 of 
the pointer, while the reflective surface 46 is in a shape gradually 
approaching a horizontal plane thereby allowing light to transmit upwards 
therethrough to prevent unevennes in brightness caused by an abrupt change 
in luminance between the front and the rear above the reflective surface. 
Further, reflective surface corner portions 50, 52 and 54 are curved to 
prevent light from being localized to form a shadow. 
A rear hollow reflecting portion 56 also functions to diffuse light 
forward, upward and rearward uniformly. 
Such hollow curved reflecting portions are formed, for example, by drawing 
sideways of the pointer at the time of molding operation. 
FIG. 7 is a sectional view of a pointer illuminating device according to 
another embodiment of the present invention, which is characteristic in 
that there are formed three hollow curved reflecting portions--front 
reflecting portion 58, central reflecting portion 60 and rear reflecting 
portion 61. 
The function of the reflecting portions 58 and 60 is the same as that in 
FIG. 6, but in the case of a large pointer, such an increase in the number 
of reflecting portions permits an efficient conduction of incident light 
to the front and rear ends of the pointer, affords a sufficient 
diffusibility upwards and thus permits a uniform illumination of the 
entirety of the pointer. 
Another embodiment of the present invention will be described with 
reference to FIGS. 8 to 13. As shown in FIG. 13, the entire upper surface 
of a pointer body 62 is exposed, and a pair of cylindrical split caps with 
ceiling 64 and 66 are attached to the pointer body 62 sideways by fitting 
(see FIG. 9). The numeral 94 denotes a transparent, central light 
receiving portion for conducting light to the pointer body 62. 
The following description is now provided about how to mount and remove the 
caps 64 and 66 with reference to FIGS. 10 to 12. 
On each of both upper right and left sides of the central light receiving 
portion 94 of the pointer 62 is formed an arm portion having a recess 70 
and a projection 72. Also on the back of the cap 64 (66) to be engaged 
with the arm portion are formed a projection 81 (74) for engagement with 
the recess 70 and a projection 78 (80) for engagement with a notched part 
76 of the projection 72 of the arm portion. Therefore, simply by pushing 
the cap 64 (66) from above, its position is decided, and it will never 
float ecdentrically back and forth in the logitudinal direction of the 
pointer body 62. 
Further, the cap 64 (66) is provided with a pair of lugs 82 and 84 (86 and 
88) in front and rear positions of its lower end. Engagement of these lugs 
with the bottom of the pointer body 62 ensures fixing of the cap 64 (66) 
without floating in any directions. 
The cap 64 (66) can be removed by first pulling out the lugs 82 and 84 (86 
and 88) conversely to the arrow shown in FIG. 10. 
In order to make such mounting and removal of the caps easier and more 
assured, it is preferable that the caps be formed of a highly elastic 
material such as an opaque resin or a metallic sheet. Being opaque is 
necessary for the prevention of light leak. 
The pointer is illuminated in the following manner. In this connection, 
reference is made to FIG. 13. 
Light from a light source (not shown) passes like arrows through a 
photoconductive plate 92 attached to the back of a dial plate 90 of the 
measuring instrument, then is reflected by a lower, conical, light 
introducing part 94 of the central light receiving portion 68 and 
conducted toward the pointer body 62 positioned above. Above the central 
light receiving portion 68 are formed cavities 96 and 98 having curved 
surfaces. Being reflected by these curved surfaces, light rays reach even 
the fore and rear end portions of the pointer body 62 uniformly, whereby 
the entirety of the pointer body 62 can be illuminated uniformly. The 
numeral 100 denotes a pointer support shaft. 
A further embodiment will be described with reference to FIGS. 14 to 16. 
FIG. 14 is a perspective view of a pointer for measuring instruments 
according to this embodiment, and FIG. 15 is an exploded perspective view 
thereof. 
As shown in FIG. 14, the entire upper surface of a pointer body 110 is 
exposed, and a front lower part of its intermediate portion, both side 
portions and a rear end portion are covered with an integral cap 106. The 
numeral 108 denotes a transparent, central light receiving portion for 
conducting light to the pointer body 110, and the numeral 112 denotes a 
pointer support shaft. 
On both sides of the intermediate portion of the pointer body 110 are 
formed projections 114, and a stepped portion 116 is formed on the lower 
surface of the rear end portion thereof. 
The integral cap 106 has a central notched portion 118 for exposing the 
upper surface of the pointer body 110, a front lower strap portion 120 
which is in contact with the bottom of the pointer body 110, and a stepped 
portion 126 of a rear strap portion 104 which stepped portion is adapted 
to engage the stepped portion 116 of the pointer body 110. 
The cap 106 can be mounted and removed in the following manner with respect 
to the pointer body 110. 
First, as shown in FIG. 16, a fore end portion 122 of the pointer body 110 
is inserted from below through the central notched portion 118 of the cap 
106. Then, with the front lower strap portion 120 of the cap 106 in 
contact with the bottom of the pointer body 110 as a fulcrum, the back of 
the cap 106 is pushed against the projections 114 of the pointer body 110, 
thereby pushing in the cap 106 to the pointer body 110 side. At this time, 
the stepped portion 126 at the rear end of the cap 106 undergoes an 
elastic deformation and is engaged with the stepped portion 116 of the 
pointer body 110. Thus, the cap 106 is mounted in a predetermined position 
easily and surely by engagement of its front lower strap portion 120 and 
rear stepped portion 126 with the pointer body 110. 
The cap 106 can be removed by disengaging its rear stepped portion 126 from 
the pointer body 110 in a direction reverse to the arrow shown in FIG. 16 
and pulling out the pointer body 110 from the central notched portion 118 
of the cap 106. 
In order to make such mounting and removal of the cap easier and more 
assured, it is preferable that the cap be formed of a highly elastic 
materila such as an opaque resin or a metallic sheet. Being opaque is 
necessary for the prevention of light leak. 
The pointer is illuminated in the following manner. In this connection, 
reference is made to FIG. 15. 
Light from a light source passes like arrows through a photoconductive 
plate 130 attached to the back of a dial plate 128 of the measuring 
instrument, then is reflected by a lower, conical, light introducing part 
132 of the central light receiving portion 108 and conducted toward the 
pointer body 110 positioned above. Above the central light receiving 
portion 108 are formed cavities 132 and 136 having curved surfaces. Being 
reflected by these curved surfaces, light rays reach even the fore and 
rear end portions of the pointer body 110 uniformly, whereby the entirety 
of the pointer body 110 can be uniformly illuminated. 
A still further embodiment of the invention will be described with 
reference to FIGS. 17 to 21. As shown in FIG. 17, the entire surface of a 
pointer body 138 is exposed, and both side faces of its intermediate and 
rear end portions are covered with an integral cap 140. The numeral 142 
denotes a pointer support shaft. 
As shown in FIG. 18, reflective projections 146 are formed on both side 
faces of an intermediate portion 144 of the pointer body 138, with a 
positioning hole 148 being formed in the upper surface of each reflective 
projection 146. Further, to the bottom of a rear end portion 150 of the 
pointer body 138 is attached a balancer 152 for taking a momental balance 
in front and in the rear with the support shaft 142 as the center. Also in 
the upper surface of the balancer 152 are formed positioning holes 154. 
On the other hand, the cap 140 has a central opening portion 156 for 
exposing the upper surface of the pointer body 138 wholly from a fore end 
portion 168 through the central portion 144 up to the rear end portion 
150, a front lower strap portion 158 which is in contact with the bottom 
of the pointer body 138, bosses 160 provided on the back of the cap for 
engagement with the positioning holes 148 of the reflective projections 
146, and bosses 162 provided on the back of the cap for engagement with 
the positioning holes 154 of the balancer 152. 
The numeral 164 denotes a colored portion which constitutes the bottom of 
the pointer body 138, and the numeral 166 denotes a colorless transparent 
portion. 
The cap 140 can be mounted to the pointer body 138 by inserting the fore 
end portion 168 of the pointer body 138 through the central opening 
portion 156 of the cap 140 and then pushing in the cap 140 with its front 
lower strap portion 158 as a fulcrum until the bosses 160 and 162 are 
fitted in the positioning holes 148 and 154. 
The cap 140 can be removed in the reverse procedure, that is, by first 
pulling out the cap 140 to disengage its bosses from the positioning holes 
148 and 154 and then pulling out the pointer body 138 from the central 
opening portion 156 of the cap 140. 
In order to make such mounting and removal of the cap 140 easier and more 
assured, it is preferable that the cap 140 be formed of a highly elastic 
material such as an opaque resin or a metallic sheet. Being opaque is for 
preventing the leak of light. 
FIGS. 19, 20 and 21 are sectional views taken on lines IXX--IXX, XX--XX and 
XXI--XXI of FIG. 17, respectively. 
In FIGS. 19 and 20, the numeral 170 denotes an opaque colored element 
fitted into the cavity in the colorless transparent portion 166 formed in 
the same manner as in the embodiment of FIG. 6, to which is mounted the 
pointer support shaft 142. The colored portion 170 has slant faces serving 
as reflective surfaces 172, which reflect and conduct incident light up to 
the fore and rear end portions 168 and 174 of the pointer. 
The pointer is illuminated in the following manner. In this connection, 
reference is made to FIGS. 22 to 24. 
Light from a light source (not shown) passes through a photoconductive 
plate 178 attached to the back of a dial plate 176 of the measuring 
instrument then is reflected vertically upward by a conical reflective 
portion 180 in which is inserted the pointer support shaft 142, and 
conducted to the transparent portion 166 of the pointer body 138 as 
indicated with arrows in FIG. 23. Then, the light rays are reflected by 
the refletive surfaces 172 of the opaque colored portion 170 and reach the 
fore and rear end portions 168 and 174 of the pointer as shown in the same 
figure. 
At the same time, as shown in FIGS. 22 and 24, light rays are once 
reflected by the reflective projections 146, then again reflected by the 
opaque colored portion 170 and reach the central portion 144, too, of the 
pointer body 138. 
Consequently, the pointer body 138 is illuminated uniformly from its fore 
end portion 168 through its central portion 144 up to its rear end portion 
150, that is, the pointer body 138 can be illuminated as a single 
continuous line. 
A still further embodiment of the present invention will be described with 
reference to FIGS. 25, 26 and 27, in which indicated at 182 is a pointer 
body, at 184 a fore end portion thereof and at 186 a rear end portion 
thereof. The numeral 188 denotes a cap which is composed of 
semi-cylindrical bodies 190 and 192 each having a ceiling. The 
semi-cylindrical bodies 190 and 192 are integrally attached by suitable 
means such as welding or fitting to the side faces of the pointer body 182 
so as to cover a photoconductive portion as will be described hereinafter. 
As shown in detail in FIGS. 26 and 27, a photoconductive portion 194 is 
formed by integral molding with the pointer body 182 so that it is 
projecting orthogonally to the longitudinal direction of the pointer body 
182, with a pointer support shaft 196 being inserted in the lower end of 
the photoconductive portion 194. The pointer support shaft 196 is 
connected to a diriving shaft of a measuring instrument (not shown) to 
support the entire of the measuring body 182. 
The photoconductive portion 194 has a conical light introducing part 200 
for receiving illuminating light from a photoconductive plate 198 and 
reflecting it upward and an inverted truncated cone-like reflecting part 
202 for intercepting and reflecting part of the light reflected by the 
conical light introducing part 200, the light introcuding part 200 and the 
reflecting part 202 being positioned concentrically with the pointer 
support shaft 196. The photoconductive portion 194 is further provided, in 
positions above the inverted truncated cone-like reflecting part 202, with 
a front reflective cavity part 203 for reflecting the light rays reflected 
by the above parts toward the front end portion 184 of the pointer body 
182 and a rear reflective cavity part 204 for reflecting those light rays 
toward the rear end portion 186. 
In such construction, illuminating light obtained through the 
photoconductive plate 198 attached to the back of a dial plate 206 is 
received and refracted upward by the conical light introducing part 200 of 
the photoconductive portion 194. Part of the thus-reflected light advances 
upward, while the remaining part is reflected outwardly of the 
photoconductive portion 194 by the inverted truncated cone-like reflecting 
part 202, then further reflected by the peripheral surface of the 
photoconductive portion 194 and becomes an upward illuminating light. The 
greater part of the illuminating light is reflected toward the fore end 
portion 184 and rear end portion 186 of the pointer body 182 by the front 
reflective cavity part 203 and rear reflective cavity part 204. Thus, the 
reflected light advancing upwardly of the photoconductive portion 194 is 
reflected in the outer peripheral direction of the latter by the action of 
the inverted truncated cone-like reflecting part 202. Consequently, a 
sufficient diffusion can be attained while suppressing convergence of 
light, that is, the illuminating efficiency can be improved. 
The inverted truncated cone-like reflecting part 202 may be changed in its 
size and the angle of its reflective portion according to the shape of the 
pointer body 182. 
By the aforementioned reflecting actions of the component parts, the 
pointer body 182 can be illuminated uniformly throughout its overall 
length. 
A still further embodiment of the invention will be described in detail 
hereinunder with reference to FIGS. 28a to 31. 
FIG. 28a is a general view of a pointer illuminating structure as assembled 
according to this embodiment; FIG. 28b is a sectional view taken on line 
B--B of FIG. 28a, showing a principal portion; FIG. 28c is a sectional 
view taken on line C--C of FIG. 28a; FIG. 28d is a sectional view taken on 
line D--D of FIG. 28a; FIG. 29 illustrates the construction of the pointer 
illuminating device; and FIGS. 30 and 31 illustrate the operation thereof. 
Referring to those figures, an elongated transparent pointer element 212 
has a light inducing section 222 at an intermediate portion thereof in the 
form of a truncated conical portion. Said truncated conical portion has a 
conical reflective surface 240. Said transparent pointer element 212 has a 
substantially flat upper surface. Referring to FIG. 29, a suitably colored 
portion 210 is applied to the underside of the transparent pointer element 
212. Said transparent pointer element 212 is made of a transparent resin 
and formed by insert molding integrally with a pointer support shaft 214 
to be connected to an internal machine (not shown). For coloring, twocolor 
molding is mainly employed. 
The colored portion 210 may be differently shaped to take balance (balance 
of moment around the pointer support shaft 214) of the entirety of the 
pointer 210. 
The transparent portion 212 has a fore end part 218 for pointing to a scale 
mark on a dial plate (not shown) of the measuring instrument, a rear end 
part 220 having a design effect. Said truncated conical portions 222 may 
be separately formed on both sides of a rectilinear portion of the pointer 
at the central part of the transparent portion 212 for conducting the 
refraction of light effectively to the fore end part 218 and rear end part 
220 of the pointer 208 as will be described later. 
Pointer caps 224 are for covering the other portions than the pointer 
portion to be illuminated, and are formed of a suitably colored resin or 
formed of a light metal such as an aluminum plate and colored. 
The pointer caps 224, for their fixing to the semi-conical reflecting 
portions 222, are each provided with a positioning guide portion 226 and, 
if they are formed of a metallic plate, are also provided with lugs 228 in 
suitable positions. 
The positioning guide portions 226 of the pointer caps 224 are fitted in 
grooves 230 formed in the semi-conical reflecting portions 222 of the 
pointer 208, and the lugs 228 are bent inwards along a bottom of each 
reflecting portion 222, whereby the paired pointer caps 224 can be 
attached to the pointer 208. 
Operation of the present invention will be described below with reference 
to FIGS. 30 and 31. 
Light (indicated with arrows) from a suitable light source (not shown) 
passes through a photoconductive plate 236 mounted on the back of a dial 
plate 234 of the measuring instrument, then is reflected orthogonally in a 
conical hole 238 in which is inserted the pointer 208, and is introduced 
into the semi-conical reflecting portion 222 of the pointer 30, where the 
light is further refracted in an orthogonal direction by a reflective 
surface 240. Since the semi-conical reflecting portions 222 of the pointer 
208 are formed generally circularly, they refract the light from the 
conical hole 238 of the photoconductive plate 236 in a substantially 
infinite orthogonal direction, which light reaches the fore or rear end 
part, 218 or 220, of the pointer 208 while repeating refraction 
(reflection) between the side faces 240 of the transparent portion 212 as 
shown in FIG. 31, whereby the transparent portion 212 can be illuminated. 
Consequently, the observer (driver) from the transparent portion 212 side 
can confirm the suitably colored portion 210. 
As shown in FIG. 32, the shape of a suitably colored portion 244 of a 
pointer 242 may be semi-circular, not triangular, and a reflective, 
surface 248 of a pointer 246 may be semi-pyramidal as indicated at 250 in 
FIG. 33. 
A still further embodiment of the present invention will be described in 
detail hereinunder with reference to FIGS. 34a to 35. 
A pointer 256 comprises a transparent portion 258 formed of a transparent 
resin such as an acrylic resin or a polycarbonate resin and a colored 
portion 260 of any desired color formed on the dial plate 1-side surface 
of the transparent portion 258. The colored portion 260 has been colored 
in a suitable color according to, for example, the well-known hot stamping 
method. Alternatively, an opaque colored resin may be subjected to an 
insert molding integrally with the transparent portion 258. Particularly, 
in the case where the colored portion 260 is formed of an opaque resin, a 
rear end portion 266 of the colored portion 260 may be formed in a special 
shape to balance the whole of the pointer 256, in other words, so as not 
to cause a moment in a plane including the pointer 256 and a pointer 
support shaft 262 with the shaft 262 as the center which shaft is for 
mounting the pointer to the driving shaft. 
The pointer 256 comprises a fore end portion 264 for pointing to a scale 
mark on the dial plate 252 of the measuring instrument, a rear end portion 
266 having a design effect and a light introcuding portion 268 positioned 
between the fore end portion 264 and the rear end portion 266 for 
introducing light into the pointer 256 and for mounting of a pointer cap. 
On both sides of the light introducing portion 268 are integrally formed 
engaging projections 270 and 272 so that the width of the pointer 256 is 
slightly larger at that portion. 
The pointer 256 is held by a holder portion 274. The holder portion 274 is 
formed of a transparent resin like the one used for the transparent 
portion 258, and its basic form is generally conical as shown in FIGS. 34c 
and 35. On its top side is formed a fitting slot 276 extending in a 
direction orthogonal to the axis of the holder portion 274, and if 
necessary, stopper pieces 278, 280, 282 and 284 are integrally formed on 
the opposed faces of both end portions of the fitting slot 276. The light 
introducing portion 268 of the pointer 256 is fitted in the slot 276, that 
is, the projecting faces of the engaging projections 270 and 272 are 
substantially opposedly contacted with the side faces of the fitting slot 
276. Further, as shown in FIG. 34b, the engaging projections 270 and 272 
are held respectively between the stopper pieces 278 and 282 and between 
the stopper pieces 280 and 284 whereby the longitudinal movement of the 
pointer 256 is restricted relative to the holder portion 274. The end 
faces of the stopper pieces 278, 280, 282 and 284 are positioned flush 
with the cone top of the holder portion 274. On the cone bottom side of 
the holder portion 274 is integrally extended a cylindrical connection 286 
which is coaxial with the holder portion. Into the connection 286 is 
press-fitted and connected one end portion of the pointer support shaft 
262. 
The holder portion 274 adjacent to both side portions of the pointer 256 is 
covered with a pointer cap 288. The pointer cap 288, which covers other 
than the portion of the pointer 256 to be illuminated, is formed of a 
suitable colored resin or formed of a light metal such as an aluminum 
plate and colored. As a whole, it is generally in the form of a short 
cylinder having one closed end, and comprises centrally divided cap halves 
290 and 292. 
The cap halves 290 and 292 are integrally formed with positioning guide 
pieces 294 and 296 respectively inwardly along the split lines of their 
closure plates, while lugs 298 are integrally formed in suitable positions 
at the respective open edge portions. After the pointer 256 is 
press-fitted and fixed in the fitting slot 276 of the holder portion 274, 
the cap halves 290 and 292 are disposed on both sides of the light 
introducing portion 268 of the pointer 256, and the respective guide 
pieces 294 and 296 are engaged respectively with stepped portions 300 and 
302 of the engaging projections 270 and 272 formed on the side opposite to 
the pointer support shaft 262, and the lugs 298 are bent inside along the 
bottom 304 of the holder portion 274, whereby the paired cap halves 290 
and 292 are fitted over the holder portion 274. To ensure the mounting of 
the cap halves 290 and 292, it is preferable that the stepped portions 300 
and 302 be inclined toward the colored portion 260 of the pointer 256. The 
cap 288 when attached to the pointer 256 is in the form of a cylinder 
whose diameter is larger than that of a driving shaft insertion hole 306 
formed in the dial plate 252. 
Operation of the present invention will now be described. Light (indicated 
with arrows) from a suitable light source (not shown) passes through the 
photoconductive plate 254 mounted on the back of the dial plate 252 and 
reaches a driving shaft insertion hole 308 formed in the photoconductive 
plate 254. The inner peripheral surface of the insertion hole 308 is a 
conical slant face 310, whereby the light incident upon the 
photoconductive plate 254 is reflected perpendicularly upward and 
introduced through the bottom 304 into the holder portion 274, where the 
light is refracted orthogonally inward by a conical peripheral surface 316 
of the holder portion 274. Since the holder portion 274 is formed 
generally conical, the light from the slant face 310 of the 
photoconductive plate 254 is refracted in a substantially infinite 
orthogonal direction as shown in FIG. 9 and reaches the fore or rear end 
portion 264 or 266 of the pointer 256 while repeating refraction 
(reflection) between side faces 312 and 314 of the transparent portion 258 
of the pointer 256 as shown in the same figure, whereby the pointer 256 is 
illuminated throughout its overall length. Consequently, the observer 
(driver) from the transparent portion 258 side can confirm the suitably 
colored portion 260. 
According to this embodiment, as set forth hereinabove, while the 
illuminating lamp is not turned on, for example, during the daytime, the 
colored portion 260 can be seen directly because the surface side 
(observer side) of the pointer is transparent, and so there can be 
provided a deep pointer. When the pointer 256 is illuminated, for example, 
during the night, light which has been refracted by the holder portion 274 
can be introduced throughout the transparent portion 258 of the pointer 
256, whereby the entirety of the pointer can be illuminated in just the 
same contents as that capable of being confirmed during the daytime with 
the colored portion 260 as a single line extending from the fore end 
portion 264 up to the rear end portion 266 of the pointer 256. Therefore, 
it is possible to provide a novel points illuminating device having an 
improved pointer visuality in a measuring instrument or the like. 
It goes without saying that the present invention is not limited to the 
foregoing one embodiment and that modifications may be made within a scope 
not departing from the gist of the present invention. For example, the 
holder portion 274 may be in the form of a pyramid as shown in FIG. 37, or 
there may be adopted such a structure as shown in FIG. 38, in which the 
peripheral surface of the shaft insertion hole 308 of the holder portion 
274 is cylindrical and a part of the holder portion 274 is inserted as an 
extension into the hole 308, with a reflection surface 322 being formed in 
the extension 320. 
According to the present invention as set forth hereinabove, the following 
effects can be obtained. 
(1) Since the central reflecting portion is formed as a hollow curved 
reflective surface which is open sideways of the pointer and the 
transmissive colored portion is formed throughout the upper surface of the 
pointer, the reflective surfaces in the interior of the pointer and the 
pointer support shaft can be covered, and for illumination at night, the 
entirety of the pointer upper surface can be illuminated as a single line 
with transmitted light. 
(2) For illumination at night, the unique reflective surfaces permit light 
introduced from below to diffuse forward and rearward throughout the 
overall length of the pointer, whereby the pointer can be illuminated 
uniformly. 
As a synergistic effect of the above (1) and (2), there can be attained 
improvement of visuality and design-related restrictions are eliminated, 
and thus the present invention can fully meet the market demand.