Light distribution system for optical encoders

Claim 2

A light distribution system for an optical encoder having an array of photosensitive sensors, [Fig. 2 (26)], said system comprising: a transparent light guide plate (28) having front and back parallel surfaces (80, 82); and characterized by: a light input coupler [Figs. 1-5 (87); Fig. 6 (90); Fig. 7 (89)] including an incident radiation distributing area (88) formed within said light guide plate for receiving a predetermined beam of input incident radiations, said distributing area spreading the input incident radiations into a distributed beam having plural beam segments (114) each being directed in said light guide plate substantially wholly parallel to a single predetermined radiation path and further being substantially parallel to said front and back surfaces; and a predetermined pattern of plural discrete light output couplers [Figs. 3, 4 (50-54)] each formed by an output reflecting surface [Fig. 5 (51, 53); Fig. 8 (160)] recessed into one of said front and back surfaces, each of the output reflecting surfaces being in optical alignment with only a single one of said predetermined radiation paths to intercept a separate one of said beam segments (147, 148), said reflecting surfaces having different surface areas corresponding to the different lengths of the predetermined radiation paths from said distributing area to produce output beams [Figs. 5, 8 (30)] for uniformly illuminating each of said sensors of said array.

Claim 3

The light distribution system as claimed in claim 1 wherein said predetermined ones of said light output couplers are spaced closer [Fig. 5 (53)] and farther (51) from said distributing area, and wherein the area of the output reflecting surfaces is smaller to intercept a narrower beam segment when closer to said distributing area and the surfaces are larger to intercept a broader beam segment for farther ones of said output couplers.

Claim 4

The light distribution system as claimed in claim 1 or 2 wherein at least two of said predetermined ones of said light output couplers (38, 39 or 51, 53) have the output reflecting surfaces thereof intercepting at least two partially overlapping beam segments (141, 142 or 147, 148).

Claim 5

The light distribution system as claimed in claim 1, 2, or 3 wherein each of said output couplers includes a flat output reflecting surface [Fig. 8 (160)] recessed into said light guide at an angle in the order of forty-five degrees.

Claim 6

The light distribution system as claimed in claim 1 or 4 wherein said incident radiation distributing area includes a circularly extending reflector [Fig. 5 (94); Fig. 7 (96)] having a circularly extended parabolic reflecting surface recessed into one of said front and back surfaces and wherein said input coupler includes a light source [Fig. 5 (91); Fig. 7 (92)] positioned at the focal point of said parabolic reflecting surface.

Claim 7

The light distribution system as claimed in claim 5 wherein said light source is formed by a semiconductor light emitting device [Figs. 5, 7 (116)] with the wafer element thereof positioned at said focal point.

Claim 8

The light distribution system as claimed in claim 6 wherein said light emitting device includes an optically transparent material [Fig. 5 (at 112)] encasing said wafer element and contiguous with one of said front and back surfaces of said light guide plate.

Claim 9

The light distribution system as claimed in claim 7 wherein said light source [Fig. 7 (92)] is integrally molded within said light guide plate.

Claim 10

The light distribution system as claimed in claim 1 wherein said predetermined patterns of light output couplers are symmetrically disposed along a single straight axis [Fig. 3 (84)] and wherein the adjacently disposed beam segments have a substantial arcuate extent for directing the separate beam segments to each of said light output couplers.

Claim 11

The light distribution system as claimed in any one of claims 4 to 9 wherein said pattern of light output couplers includes plural groups of circularly disposed output couplers [Figs. 1-4] substantially evenly positioned on either side of a center vertical reference axis (97) of said light guide plate extending through the center of said input coupler so that substantially equal numbers of the beam segments are spread out from said distributing area on either side of said vertical reference axis.

Claim 12

The light distribution system as claimed in claim 10 wherein said light guide plate includes a plurality of hole openings (37, 43, 49, 55, 61) for receiving dial pointer shafts (20, 22) associated with each of separate register dials (not shown) to be encoded and wherein each group in said pattern of light output couplers circumscribes each of said hole openings.

Claim 13

The light distribution system as claimed in claim 1 or 4 wherein said incident radiation distributing area includes a circularly extending reflector [Fig. 6 (95)] having a ninety degree conical reflecting surface and wherein said input coupler includes a light source for producing said input radiations along the center axis of said conical reflecting surface.

Claim 14

The light distribution system as claimed in claim 12 wherein said light source is formed by a semiconductor light emitting device having a collimating lens [Fig. 6 (118)] aligned with said center axis (97) of said conical. reflecting surface.

Claim 15

The light distribution system as claimed in claims 1 to 13 wherein said light guide plate further includes plural intermediate reflectors [Fig. 1 (96, 97); Figs. 3, 4 (98, 99); Fig. 10 (98')] each positioned for redirecting predetermined ones of said beam segments from said light input coupler to predetermined ones of said light output couplers so that the predetermined ones of said beam segments are directed in a bent and indirect manner to the predetermind ones of said light output couplers.

Claim 16

The light distribution system as claimed in claim 14 wherein at least one of said intermediate reflecting surfaces is formed along a common edge of said light guide plate.

Claim 17

The light distribution system as claimed in claim 14 or 15 wherein said intermediate reflecting surfaces are formed along at least two different edges of said light guide plate.

Claim 18

The light distribution system as claimed in claim 16 wherein said at least two intermediate reflectors are formed by at least two peripheral edges [Figs. 3, 4 (98, 99)] of said light guide plate and wherein a further one of said plural intermediate reflectors is formed by an edge (104) partially forming one of said hole openings (37) in said light guide plate.

Claim 19

The light distribution system as claimed in claim 15, 16, or 17 at least one of said intermediate and reflecting surfaces is formed with a concave reflecting surface [Fig. 9 (167); Fig. 10 (206, 208)].

Claim 20

The light distribution system as claimed in claims 1, 2, or 3 wherein each of the output reflecting surfaces is concave [Fig. 9 (167)].

Claim 21

A light distribution system for a meter dial register encoder having an array including groups of circularly disposed photoconductive sensors [Fig. 2 (26)], wherein said light distribution system comprises: a light source [Fig. 5 (91)]; a flat transparent light guide plate (28) having opposite front and back parallel surfaces (80, 82) terminated by edge surfaces [Fig. 1 (96, 97); Figs. 3, 4 (98, 99)] defining an elongated horizontal configuration; and characterized by comprising: a light input coupler [Figs. 3, 4, 5 (87); Fig, 6 (90); Fig. 7 (89)] for mounting said light source at the light guide plate and said input coupler including an incident radiation distributing area (88) arranged for receiving a predetermined beam of input incident radiations from said light source, said distributing area being formed by a recessed circularly arcuate reflecting surface [Figs. 3, 4, 5 (94); Fig. 6 (95); Fig. 7 (96)] in said light guide plate effective to produce a flat distributed beam ' uniformly spread out along individual radially extending beam segments [Figs. 4, 5 (147, 148); Fig. 6 (114, 120); Fig. 7 (114)] extending substantially parallel to the opposite light guide plate surfaces; a pattern of light output couplers [Figs. 3, 4 (50-54)] symmetrically disposed with respect to said input coupler and optically aligned with said array of sensors, each of said light output couplers including an output reflecting surface [Fig. 5 (51, 53); Fig. 8 (160)] extending at substantially the same angle into a common one of said opposite surfaces of said light guide plate so as to have a predetermined optical alignment for intercepting separate ones of said beam segments (147, 148) and for reflecting individual output beams [Figs. 5, 8 (30)] in a substantially collimated manner to uniformly illuminate said array including groups of circularly disposed photoconductive sensors (26).

Claim 22

A light distribution system for a meter dial register encoder having an array including groups of circularly disposed photoconductive sensors [Fig. 2 (26)], wherein said light distribution system comprises: a light source [Fig. 5 (91)]; a flat transparent light guide plate (28) having opposite front and back parallel surfaces (80, 82) terminated by edge surfaces [Fig. 1 (96, 97); Figs. 3, 4 (98, 99)] defining an elongated horizontal configuration; and characterized by comprising: a light input coupler [Figs. 3, 4, 5 (87); Fig, 6 (90); Fig. 7 (89)] for mounting said light source at the light guide plate and said input coupler including an incident radiation distributing area (88) arranged for receiving a predetermined beam of input incident radiations from said light source, said distributing area being formed by a recessed circularly arcuate reflecting surface [Figs. 3, 4, 5 (94); Fig. 6 (95); Fig. 7 (96)] in said light guide plate effective to produce a flat distributed beam ' uniformly spread out along individual radially extending beam segments [Figs. 4, 5 (147, 148); Fig. 6 (114, 120); Fig. 7 (114)] extending substantially parallel to the opposite light guide plate surfaces; a pattern of light output couplers [Figs. 3, 4 (50-54)] symmetrically disposed with respect to said input coupler and optically aligned with said array of sensors, each of said light output couplers including an output reflecting surface [Fig. 5 (51, 53); Fig. 8 (160)] extending at substantially the same angle into a common one of said opposite surfaces of said light guide plate so as to have a predetermined optical alignment for intercepting separate ones of said beam segments (147, 148) and for reflecting individual output beams [Figs. 5, 8 (30)] in a substantially collimated manner to uniformly illuminate said array including groups of circularly disposed photoconductive sensors (26).

Claim 23

A light distribution system, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

Claim 24

A light distribution system, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.