CN100350308C - Backlight with structured sufaces - Google Patents

See also Fig. 1, an

10 comprises a

12; One light emitted

14; One

16, this light guide way have an

18, a

20, an

21 and one

22; One reflecting

24 near the

20; One first light is redirected

26; One second light is redirected

28; An and reflective polarizer 30.

16 can be wedge shape, its modification or a flat board.As everyone knows, the purposes of light guide way is that the light from

12 is distributed to a zone much larger than

12, more particularly, roughly is distributed to the whole zone that is made of output surface 18.

16 preferably can also be realized these tasks with compact, thin unit.

12 can be one light to be input to the cold-cathode fluorescence lamp (Cold Cathode Fluorescent Lamp (CCFL)) of the

21 of

16, and

14 can be one around

12 to form the reflectance coating in lamp

24 is positioned at the back of

16, the close back side 20.

24 can be effective backreflection body, for example a diffusive reflective film or a specular reflection film.

In illustrated embodiment, the light of edge combination is propagated to end

22 from importing

21, and this is limited by total internal reflection (TIR).TIR is invalid can to draw light from

16 by making.Because key groove, being limited to light in the

16 increases incident angle with respect to the plane of roof and diapire, and each TIR is gone up.Thereby because light no longer is subjected to the restriction of TIR, it reflects

18 the most at last, and with its formation one glancing angle.Some light are drawn the back side 20.By

24 these light are reflected, enter and by light guide way 16.First light is redirected

26 and is configured to a turning film, redirects along roughly parallel with preferable direction of observation direction so that leave these light of

18.

Still referring to Fig. 1 and briefly referring to Fig. 2, it can be one to have the transmittance optical thin film of a

32 and a

34 that first light is redirected element 26.In a turning film was used,

32 was configured to an input surface, and is formed with

44, and it can reflect and reflect the light that leaves

16 along preferable direction of observation.Therefore

34 is an output surface.Prism can have a roughly uniform structure, perhaps can have one as being numbered No.09/415,873, be filed in the described heterogeneous texture of common transfer U.S. Patent application " optical thin film with variable angle prism " on October 8th, 1999, this paper will quote its disclosure as a reference.

Please return referring to Fig. 1, in every kind of structure of

10, can not need second light to be redirected element 28.When the redirected element of second light is included in the

10, it can be a diffuser, a lensing distributor (lenticular spreader) or a prismatic film, for example the brightness enhancing films of the 3M brightness enhancing films product that can buy from the 3M company in Sao Paulo, Minnesota State city (selling as BEFII or BEFIII) and so on.

30 can be one inorganic, polymerization or cholesterol (cholesteric) liquid crystal polariscope film.One suitable film is diffuse reflection polariscope film product (selling as DRPF) or direct reflection polariscope film product (selling as DBEF), and they all can be buied from 3M company.In addition, second light can be redirected at least

28 and

30, and first optics may be redirected

26 and be combined into a single optical element.Be entitled as " method of the brightness in display illumination device and the increase display illumination device ", be numbered No.09/415,100, the common transfer U.S. Patent application that is filed on October 8th, 1999 has been narrated the optical texture of several such combinations, and this paper will quote its disclosure as a reference.

Use is used for the light guide way of back illumination, and for example the

16, has unevenness usually from the light of light guide way output.These unevenness concentrate near the

21 usually.In order to hide the unevenness that is counted as defective usually, use the diffuser of the output surface of a covering light guide way usually.Yet a diffuser can reduce the overall brightness of display, and is not enough to hide all defect.

As mentioned above, in

10, first light is redirected

26 and is configured to a turning film, and can have a structure shown in Figure 2.Refer again to Fig. 2, film comprises the

42 of an optical texture 40 (prism), and these optical textures are configured to have the variable wave amplitude of an out-phase.Use for turning film,

42 is formed on the surface, and this surface is the light input surface of film.Yet in several other that this paper will narrate used,

42 can be formed on the end face and/or bottom surface of voussoir, flat board or film.Use for turning film shown in Figure 1, the prism on the

32 that is formed on the redirected

26 of first light,

34 can be formed with optical texture.

Continuation is discussed in conjunction with Fig. 2, and first optics is redirected

26 and has one

36 and one second edge 38.

40 extends from

36 towards

38 in pattern 42.Each

40 can have numerous characteristics, for example the aspect ratio of wave amplitude, cycle and crest and trough 46.

42 can also have some characteristics, for example the spacing p between the optical texture 40.

40 shown in Figure 2 has amplitude change.In the application of the first

26, all grooves can be arranged to make the variation of its wave amplitude vertical with light source 12 (Fig. 1).

Continuation is referring to Fig. 2, and obviously in

42,

40 is formed with the bigger amplitude change of quantity at 36 places, first edge, and the quantity of this amplitude change reduces towards second edge 38.Because surperficial gradient is high more, the amplitude change that the quantity in the

40 is bigger produces big more luminous power along the fluted shaft line.So, the luminous power of this pattern reduces with a function of the distance of leaving first edge 36.The setting of this

40 and

42 is autotelic.As described, the unevenness in the output of

16 can concentrate near the

21, and

21 unevenness more at a distance is few more.Thereby

40 and

42 provide more diffusion near being provided in first edge 36.In application,

36 is set near the

21 of

16 basically.

42 has a spacing p, and this spacing can be even or variable, and the wave amplitude of

40 is reduced to zero towards second edge 38.With discussed in detail, can make this pattern as below with any tool shape.

Should be understood that, use ray trace and other analytical technology, can be identified for the specific setting of

40 and

42, these are provided with the unevenness that special survey arrives in the output that can proofread and correct

16 best.That is to say, can design one or more characteristics of

40 and

42, to proofread and correct specific unevenness.As mentioned above, be redirected

26 about first light,

40 and

42 offer the output of importing near the

16 surperficial 21 with luminous power, import near surperficial 21 unevenness so that hide to appear at.Because usually observe the more weak or less unevenness of intensity from

16, so the luminous power that provides away from surperficial 21 places of input is less or luminous power is not provided from surperficial 21 farther places of input.In this kind mode, provide luminous power in the position that needs most covering or softening unevenness, and provide less luminous power in the less position of unevenness to be hidden.In addition, by increasing the characteristic of optical texture and/or change optical texture, in fact luminous power can be increased to any position of light guide way output.In addition, to need not be uniform in the increase of luminous power.The substitute is, if necessary, can as required luminous power be increased to the zone of dispersion of light guide way output, to assist the covering defective or to cause specific optical effect.

Please in conjunction with Fig. 3, a

50 has a

52, forms this surface and makes it comprise a plurality of

54 that are arranged in the pattern 56.

54 is configured to replace the diffusion dot pattern that is used for drawing from the light guide way light basically.Although in Fig. 3, be shown as ellipse,

54 is not confined to any given shape jointly, they are not confined to any one given shape in the

56 yet.Therefore,

54 can be prism, straight line, point, square, ellipse, circle, rhombus or the combination that roughly is Any shape or different shape.In addition, can make the size of

54 very little, and in

56 tight spacing together, thereby than the size of all points in the diffusion dot pattern and much smaller at interval.For example, optical texture can have the size that reaches the typical sizes that is used for diffusion point, but best acuity less than human eye, and can be apart from one another by in about 50-100 micron.The very small dimensions of

54 and tight spacing are eliminated or have been reduced the required diffusion of light guide way output, and this pattern of normally hiding diffusion point is necessary.

See also Fig. 4, optical

51 has a

53, and this surface forms a plurality of

55 that are arranged in the pattern 57.In this embodiment of the present invention,

55 forms circle or point.Fig. 5 shows a light

59 with

61, and this back side is formed with the

63 that is arranged in the pattern 65.These optical textures also are depicted as circle or point, but should be understood that optical texture in fact can adopt any structure.

Although hereto discuss according to optical thin film, the present invention can be applicable to light guide way voussoir itself.See also Fig. 6 and 7, one smooth guide waies 60 and have

62, one

64 and a back side 66.

62 is configured to be positioned near the light source (not shown), so that the light source that incides

62 to be provided.As the invalid result of TIR who makes in the

60, the light that incides

62 is drawn output surface 64.As discussed above, from the light of

60 outputs, has unevenness usually, especially near

62.

Fig. 7 shows luminous power is increased to the

66 of

60 and adjusts the intensity that

62 is left in extension.As shown in Figure 6, the

66 is formed with homophase

68, and this optical texture is configured to strengthen near 62 the drawing of input surface, and

62 and reduce to zero gradually with it.Pattern can not reduce on whole surface gradually yet, and is promptly constant, and its increase of starting from scratch changes arbitrarily or is distributed in the zone of dispersion.Optical texture also can be an out-phase, forms optical texture 68 ' in the back side 66 ' of light guide way 60 ' for example shown in Figure 8.Should be understood that, the pattern of optical texture also can be formed in the

64 separately, perhaps be formed on the

66 in pattern combine---below will narrate this embodiment of the present invention in more detail, especially in conjunction with Figure 15 and 16.Turn back to this discussion, the purpose that optical texture is provided is to obtain to make the minimized effect of unevenness that no matter may occur in light guide way where output.For example, the

60 shown in Fig. 6 and 8 can have near the mainly

62, and this is increased in suggestion near the optical texture that has bigger luminous power the

62.

Please especially in conjunction with Fig. 7,

68 can be formed on the

72 of optical thin film 70.Then, use the wedge structure that ultraviolet ray (UV) is solidified, tackifier pressure-sensitive or that other is suitable is connected to optical

70 light guide way 60.Perhaps, can become piece molded voussoir, to comprise

68 in 66 overleaf.

As an example of above-mentioned feature of the present invention, and in conjunction with Fig. 9, a linear Fresnel lens or

80 have a

82 and a

84 that roughly is the plane.

84 is formed with

86, and additional

88 is superimposed upon on the lens arrangement 86.

88 has some characteristics, for example wave amplitude, cycle and aspect ratio, and they change to one

92 of

80 from one

90 of lens 80.

80 can become piece to constitute, and perhaps as shown in Figure 9, comprise that the

86 of

88 can be formed on the

94, then this film are adhered to into the optical base-

96 of piece.According to application,

82 can be arranged to an input surface, and

84 is arranged to an output surface, vice versa.

Figure 10 and 11 shows a

81, and this round lens comprises a

83 and a second surface 85.Formation comprises the

85 of

87, circular Fresnel lens structure for example, and additional

89 is superimposed upon

87 tops.

89 has some characteristics, for example wave amplitude, cycle and aspect ratio, and for example, they can change to the center of

81 from an excircle of

81.

See also Figure 12 now, the figure shows a

100, this film comprises the

102 of the amplitude change of the

108 that use " V " shape cutting

102 can be formed on the end face and/or bottom surface of film 100.Equally,

102 can be formed in a voussoir or the

100 has one

104 and one second edge 106.The

108 that is arranged in the

102 extends from first edge towards second edge 106.Each

108 can have numerous characteristics, for example wave amplitude, cycle and

102 also can have some characteristics, for example limits spacing p at interval between the optical texture 108.

108 shown in Figure 12 has amplitude change.In the application of

100, the variation that all grooves can be arranged to make its wave amplitude is vertical, parallel with the light source of the light guide way of

100 or at angle.

Continuation is referring to Figure 12, and obviously in

102,

108 forms bigger wave amplitude at 104 places, first edge, and wave amplitude reduces towards second edge 106.Because surperficial gradient is high more, bigger wave amplitude produces big more luminous power along the fluted shaft line.So, the luminous power of this pattern reduces with a function of the distance of leaving first edge 104.The setting of this

108 and

102 is autotelic.

Consult Figure 13 and 14, they show film 110 and 112 respectively.Each film 110 and 112 has the characteristic identical with

100, and uses identical label to narrate same section between them.One " V " shape instrument formation pattern is opposite with using, and the film 110 of Figure 13 has a pattern 114 of the optical texture 116 that uses the instrument formation with a curve or arcuate structure.The film 112 of Figure 14 has the pattern 118 of the optical texture 120 of a use flush end instrument formation.Pattern 114 and 118 is configured to described situation, so that provide luminous power in surperficial or all surfaces of film 110 and 112.Should be understood that, that any tool construction in fact can use with selecteed particular tool, so that in surperficial or all surfaces of film, obtain the luminous power of desired amt and form.

In the

121 shown in Figure 15 and 16, one

122 of

124 is formed in the

126, and one

128 of

130 is formed in the

132 of voussoir 134.Just for illustrated purpose,

124 shown in Figure 15 only part extends and crosses

126, and

130 shown in Figure 15 only part extend and cross end face 132.Should be understood that, that

124 and

130 will in most of the cases extend respectively crosses

126 and end face 132.

122 can be configured to help extracting the light from

134, and

128 can be configured to hide the unevenness from the light output of voussoir.Yet, should be understood that, that the pattern of realization in the

134 will depend on and will export from the ideal light rays that voussoir 134 obtains.In addition, as mentioned above,

122 and 128 can at first be formed in the optical thin film, then optical thin film is connected to voussoir, for example by bonding.In another structure,

122 and 128 is formed in the voussoir by injection molding or casting.

As shown in the figure, the orientation of

152 is vertical with

142 basically.The orientation that should be understood that,

152 can be parallel with

142, or with a angle between 142 one-

0 of light sources degree is spent with 90.

Turning

148 can be any suitable prism vergence film.For example, narrate in the U.S. Patent application that turning

148 can be formed as previous described being entitled as " optical thin film with variable angle prism ".

Formation comprises the

154 of optical texture 152.This will cause comparing with the light of drawing from the

154, draw some other light by

150 from light guide way 144.The light that a part is left the

154 will run into

146, and reflect by

144 and

150.

As shown in the figure, the orientation of optical texture 152 ' is vertical with light source 142 ' basically.The orientation that should be understood that, optical texture 152 ' can be parallel with light source 142 ', or with a angle between 142 one-

0 of light sources degree is spent with 90.

Formation comprises the output surface 150 ' of optical texture 152 ', and this will cause comparing with output surface 150 ', draw other light by the back side 154 ' from light guide way 144.Also draw some light from

150 '.The light that a part is left the back side 154 ' will run into backreflection body 146 ', and will reflect by light guide way 144 ' and output surface 150.Therefore, for back of the body illuminator 140 ', preferably backreflection body 146 ' is directly fixed on the

154 '.This can be achieved by backreflection body 146 ' is laminated to the

154 '.Be numbered 09/414,124, be filed on October 8th, 1999, be entitled as and disclose in the common transfer United States Patent (USP) of " have directly the light guide way of fixing reflecting body and the manufacture method of this light guide way " and narrated this setting that is used for backreflection body 146 ', this paper will quote its disclosure as a reference.Perhaps, can use the vapor deposition process that the backreflection body is formed goes up overleaf.Be directly fixed among the embodiment at the light guide way back side at reflecting body, should be understood that, that reflecting body must be a minute surface, efficient and have a low absorptivity.

As mentioned above, increase and be respectively formed at the back side of light guide way or the characteristic variations of the optical texture in the

152 and 152 ', the amplitude change of optical texture for example is with the unevenness in the output that reduces back of the

140 and 140 ' respectively.Can in optical texture, provide similar variation by other method, for example to optical texture spray pearl (bead blasting), yet all grooves that form the described variation with prism height provide the preferred approach of the unevenness in a kind of may command, the output of predictable minimizing back of the body illuminator.

Also have some and in the output surface 150 ' of light guide way 140 ', provide optical texture 152 ' (characteristic that comprises variation) relevant attendant advantages.An advantage like this relates to the interphase of output surface 150 ' and turning film 148.For the optical texture 152 ' that is formed in the output surface 150 ', has less relatively contact point between the prism of turning

148 and

150 '.This can cause being commonly called the optical defect of soaking and reduce.As mentioned above, the form that changes optical texture 152 ' also helps to hide the defective in the output of carrying on the back illuminator, makes light output more even.Therefore, in output surface 150 ', provide another advantage of optical texture 152 ' can eliminate diffuser film in the whole backlight system.As can be observed from Figure 20, owing to optical texture 152 ' provides the parallel light calibration, so the present invention can provide the backlight system of comparing the less optical thin film sheet material of needs with typical backlight system.

Figure 21 shows a

151, a

153, a

154 and a backreflection body 155.Draw light from the

161 and the

157 of light guide way 151.

156 between the

155 and the

157 can hold back quite a few from the

157 light of drawing.This light finally can scatter and disappear, thereby causes inefficiency.In order to improve this situation, as shown in figure 22, the reflecting surface 158 of backreflection body 155 ' can be formed with optical texture.Optical texture can be that plane, groove or other have the structure of shape.Optical texture helps to reduce the direct reflection composition from backreflection body 155 ', and guides more rays upwards by

151, thereby increases its efficient.One backreflection body suitable, that comprise optical texture is enhancement mode diffuse reflector (EDR) film product of being sold by 3M company.Those skilled in the art will be clear that the principle of telling about among Figure 22 in fact can be applicable to any back of the body illuminator, include but not limited to carry on the back the backlight system of the additional preferred embodiment of

140 and this paper narration.

In Figure 23, back of the

160 comprises that a

162, a wedge shaped light guide are to

164, a

166, a

168 and an optional additional optical films 170.Light guide

164 has an

165 and a

172, this back side be formed with combine Figure 16 in

134 shown in

124 or 130 similar optical textures.Optical texture can be formed directly in the

164 by injection molding or casting.Perhaps, optical texture can be formed on one and be laminated to photoconduction in the transmittance film at the

172 of

164.

Use is formed on the optical texture on the

172 of

164, and the light that leaves

164 by

165 is compared with the

172 to some extent and increased.Yet the light that leaves the

172 runs into

166, and reflects by light guide way 164.One comprises that the suitable reflecting body of optical texture is the diffuse reflector of a trough of belt.

Additional aspect according to back of the

160 can be formed on the

168 that comprises a diffuser structure in its output surface 176.Optional optical

170 can be a brightness enhancing films, BEFIII optical thin film for example above-mentioned, diffuse reflection polariscope film product (selling as DRPF) or direct reflection polariscope film product (selling as DBEF), these products can be buied from 3M company.

In Figure 24, back of the body illuminator comprises that a

182, a wedge shaped light guide are to

184, a

186, a

188 and an optional optical thin film 190.Light guide

184 has an

192, and this output surface is formed with the optical texture similar with combining the

152 shown in the

144 shown in Figure 17.Can form

184 by injection molding or casting, so that optical texture is included in the output surface 192.Perhaps, optical texture can be formed on one and be laminated to photoconduction in the transmittance film of the

192 of body 184.This set can increase the manufacturing dirigibility, and is used for the mould design of

184 to reduce manufacturing cost by simplification.Being substituted by each photoconduction to what system was made unique mould is, by a surface of light guide way is stacked so that the light guide way is suitable for the present invention with the optical thin film that is formed with optical texture.

Use is formed on the optical texture on the

192 of

184, leave from

192 amount of light of

184 with from the

193 amount of light of leaving the light guide way compare to some extent and increase.Yet the light that leaves the

193 runs into

186, and reflects by light guide way 184.Reflect by the number percent of

184 higherly in order to ensure the light that leaves the

193, preferably

186 is directly fixed on the back side 193.This can by with a minute surface or minute surface pellicular cascade to the

193 or be achieved by vapor deposition coated back surface 193.When being directly fixed on the

193, the backreflection body must be a minute surface and efficiently.

Additional aspect according to back of the body illuminator can be formed on the

188 that comprises a diffuser structure in its output surface 196.Optional optical

190 can be a brightness enhancing films, BEFIII optical thin film for example above-mentioned, diffuse reflection polariscope film product (selling as DRPF) or direct reflection polariscope film product (selling as DBEF), these products can be buied from 3M company.

In Figure 25, back of the

220 comprises that a

222, a wedge shaped light guide are to

224, a

226 and a turning film 228.Light guide

224 has an

230 that is formed with the optical texture (not shown).Optical texture can have the change pattern of the cutting tool formation of any suitable shape of a use, the pattern of narrating in the U.S. Patent application of for example formerly mentioning that is entitled as " optical thin film ".Can in

224, directly form optical texture by injection molding or casting, perhaps, optical texture can be formed on one and be laminated to photoconduction in the transmittance film of the

230 of

224.

Use is formed on the optical texture on the

230 of

224, and the amount of light of leaving

224 by the

232 is compared with the amount of light of leaving by

230 to some extent and increased.This light runs into

226, and reflects by light guide way 224.One suitable reflecting body can be the diffuse reflector of a trough of belt.Optical texture can also hide unevenness, and thereby has eliminated the needs of diffuser in backlight system.

Equally, but since optical texture also collimation leave the light (seeing Figure 20) of light guide way, so the present invention can provide and compares the less backlight system of required optical thin film sheet material with typical backlight system.In the embodiment shown in Figure 25, have individual optional optical

238, this film can be diffuse reflection polariscope film product (selling as DRPF) or the direct reflection polariscope film product of buying from 3M company (selling as DBEF).

In Figure 26, back of the

200 comprises that a

202, a wedge shaped light guide are to

204, a

206 and one or more additional, optional optical thin film 210 and 212.Light guide

204 has a

214, this back side be formed with combine Figure 17 in

144 shown in the similar optical texture of optical texture 152.Can in

204, directly form optical texture by injection molding or casting.Perhaps, optical texture can be formed on one and be laminated to photoconduction in the transmittance film at the

214 of

204.

The optical texture that is formed on the

214 of

204 helps drawing light from light guide way 204.Therefore, optical texture can be eliminated the diffusion dot pattern that is generally used for drawing from the light guide way light.Some light leave the

214, and this light runs into

206, and reflect by light guide way 204.A kind of suitable backreflection body is enhancement mode diffuse reflector (EDR) film product that 3M company sells.

Elimination is used for extracting dot pattern from the light of

204 and can reduces and increase diffusion appears at the output of back of the

200 with covering the needs of dot pattern.Optional optical

210 and 220 can be a brightness enhancing films, the BEFIII optical thin film that is arranged in arranged in a crossed manner for example above-mentioned; Diffuse reflection polariscope film product (selling as DRPF), direct reflection polariscope film product (selling as DBEF) and/or its multiple combination, these products can be buied from 3M company.

In Figure 27, back of the

240 comprises that a

242, a wedge shaped light guide are to

244, a

246, a

248 and first, second optional additional

250 and 252.Preferably use a tackifier with dot pattern that backreflection

246 is fixed in the

254 of

244, the tackifier of narrating in the U.S. Patent application of for example formerly mentioning that is entitled as " have directly the light guide way of fixing reflecting body ".Therefore, with tackifier with some pattern setting, a leading point pattern normally.

244 has an

255 that is formed with the optical texture (not shown).Optical texture can have as mentioned above a change pattern.Can in

244, directly form optical texture by injection molding or casting, perhaps, optical texture can be formed on one and be laminated to photoconduction in the transmittance film of the

255 of

244.

As described, comprise that the optical texture of change pattern can eliminate the needs of diffuser (for example diffuser 248), with the dot pattern in the output that hides back of the

240 and other unevenness.Thereby

248 is optional.In use, optional optical

250 and 252 can be a brightness enhancing films, BEFIII optical thin film product, diffuse reflection polariscope film product (selling as DRPF) or the direct reflection polariscope film product (selling as DBEF) that is arranged in arranged in a crossed manner for example above-mentioned, these products can be buied from 3M company.

See also Figure 28 now, back of the

260 comprises that a

262 and a plan wedge shaped light guide are to body 264.Intend wedge shaped light guide and comprise a

266 and a

268 to body 264.First surface can be formed with

270, for example the optical texture of narrating in conjunction with Figure 17 152.Second surface can form the

272 of band facet, and this structure is configured to parallel with light source 262.The

272 of band facet helps drawing light by the inefficacy that strengthens total internal reflection from the light guide way.Although not shown, back of the

260 comprises that also one is arranged near the backreflection body the

268.

The

272 of band facet has variable corner characteristics.Each independent facet has a facet angle.When the

272 of band facet comprised a variable corner characteristics, each facet angle changed with different facets.This set of the

272 of band facet can make the unevenness in the output that appears at back of the

260 reduce.

Although

264 is depicted as a slab construction, when guide

264 can be a wedge shape.In addition, the

272 of band facet can be formed directly in the

264, for example, perhaps the groove structure of band facet can be formed on one and be laminated to flat board or wedge shaped light guide in the optical thin film of body by molded or casting.The groove structure of band facet also can make density change with a function of the distance of leaving

262.

1. photoconduction comprises:

One first surface;

A second surface relative with first surface;

One input edge surface, described input edge surface extends between first surface and second surface;

A plurality of prism grooves that are formed in the first surface, described prism groove has a fluted shaft line separately, and every fluted shaft line basically with other fluted shaft line parallel, wherein, the fluted shaft line is aligned to and is substantially perpendicular to the input edge surface; And

Each prism groove in a plurality of prism grooves has a characteristic that influences the optical property of prism groove, this characteristic is at least a in wave amplitude, aspect ratio and the spacing of prism groove, and this characteristic changes along the fluted shaft line that extends from the input edge surface along with the function of position.

2. photoconduction as claimed in claim 1 is characterized in that, the characteristic variations of adjacent prisms groove is one of homophase and out-phase.

3. photoconduction as claimed in claim 1 is characterized in that, this characteristic is aligned to along the fluted shaft line has big more numerical value in the position that is positioned at the closer to the input edge surface.

4. photoconduction as claimed in claim 1 is characterized in that, this characteristic comprises along the length of fluted shaft line having discrete characteristic variations.

5. photoconduction as claimed in claim 1 is characterized in that, this characteristic comprises along the length of fluted shaft line having continuous characteristic variations.

6. photoconduction as claimed in claim 1, it is characterized in that, this characteristic is relevant with the optical energy of prism groove, and optical energy from being positioned near the position on the fluted shaft line at input edge to being positioned at away from the position on the fluted shaft line at input edge, is reduced to less than the second value of first numerical value along the fluted shaft line gradually from first numerical value.

7. photoconduction as claimed in claim 1 is characterized in that, comprises a plurality of prism grooves that are formed in the second surface.

8. photoconduction as claimed in claim 1 is characterized in that, comprises the diffusing pattern that is formed in the second surface.