CN100570878C

CN100570878C - Light sensor and display panel with the same

Info

Publication number: CN100570878C
Application number: CNB2007101397193A
Authority: CN
Inventors: 卓恩宗; 彭佳添; 林昆志; 江文任; 陈至扬; 林崇荣; 金雅琴; 赵志伟; 翁健森; 甘丰源
Original assignee: AU Optronics Corp
Current assignee: AUO Corp
Priority date: 2007-07-27
Filing date: 2007-07-27
Publication date: 2009-12-16
Anticipated expiration: 2027-07-27
Also published as: CN101106143A

Abstract

The invention relates to a light sensor, which comprises a sensing thin film transistor and a light diode. The sensing thin film transistor is provided with a grid electrode and a base electrode. The photodiode has an intrinsic semiconductor region electrically connected to the gate and the base of the sensing TFT. The sensing thin film transistor and the photodiode are of a structure containing low-temperature polysilicon materials. A display panel including the photo sensor is also disclosed.

Description

OPTICAL SENSORS and display floater with this OPTICAL SENSORS

Technical field

The invention relates to a kind of OPTICAL SENSORS, and particularly relevant for a kind of OPTICAL SENSORS that is used for display floater and comprises the low temperature polycrystalline silicon material of supplying, is about a kind of OPTICAL SENSORS and display floater with this OPTICAL SENSORS specifically.

Background technology

Fig. 1 is the schematic diagram of traditional PI N optical diode 100.Intrinsic (intrinsic) semiconductor regions 106 that PIN optical diode 100 comprises N type semiconductor zone 102, P type semiconductor zone 104 and is positioned at N type semiconductor zone 102 and regional 104 of P type semiconductor.When irradiate light arrives intrinsic semiconductor region 106, move toward P type semiconductor regional 104 and N type semiconductor zone 102 respectively because of the electric hole (h+) and electronics (e-) meeting of photoelectric effect generation, so produce photoelectric current.Prior art just can be used as optical inductor with this PIN optical diode 100 and use by measuring this photoelectric current.

Generally speaking, the OPTICAL SENSORS that application of cold temperature polycrystalline SiTFT (Low Temperature PolySilicon-Thin film transmitter) technology is made, because its base material thickness that can be used for light absorption only is about 50 rice how, therefore have the shortcoming of low photosensitivity.Except the shortcoming of low photosensitivity, traditional PIN optical diode is influenced by its manufacturing process and has the dark current problem of higher unavoidably.In addition, based on the consideration of manufacturing process, use can possess the CMOS manufacturing process of n+ and p+ implanting ions step simultaneously and make the complexity that the PIN optical diode also can increase manufacturing process.Therefore, though prior art has proposed the scheme of many raisings or improvement OPTICAL SENSORS usefulness, can't be suitable for or integrate the TFT manufacturing process that is compatible with present display application fully.

Summary of the invention

According to one embodiment of the invention, a kind of OPTICAL SENSORS is proposed.This OPTICAL SENSORS comprises a sensing film transistor and an optical diode.The sensing film transistor has a grid and a base stage.Optical diode has an intrinsic semiconductor region and the transistorized grid of sensing film and base stage and electrically connects.Sensing film transistor and optical diode are the structure that comprises the low temperature polycrystalline silicon material.

According to another embodiment of the present invention, a kind of display floater is proposed.This display floater comprises substrate, a liquid crystal layer and a plurality of pixel cell of a pair of corresponding setting.Liquid crystal layer is arranged at this between the substrate, and pixel cell is arranged at this on the substrate.Each pixel cell comprises a light sensing zone and a viewing area.Include an OPTICAL SENSORS and in the light sensing zone and read thin-film transistor.OPTICAL SENSORS comprises a sensing film transistor and an optical diode.The sensing film transistor has a grid and a base stage, and optical diode has an intrinsic semiconductor region and transistorized grid of sensing film and base stage electric connection.Read thin-film transistor in order to read the signal that OPTICAL SENSORS produces.

Description of drawings

For above and other objects of the present invention, feature, advantage and embodiment can be become apparent, being described in detail as follows of accompanying drawing:

Fig. 1 is the schematic diagram of traditional PI N optical diode;

Fig. 2 A illustrates the top view of an OPTICAL SENSORS according to one embodiment of the invention;

Fig. 2 B is the corresponding structural representation of the OPTICAL SENSORS of Fig. 2 A;

Fig. 3 A illustrates the top view of a display floater according to one embodiment of the invention;

Fig. 3 B is the profile of Fig. 3 A along AA ' line;

Fig. 3 C is the corresponding structural representation of the OPTICAL SENSORS among Fig. 3 A; And

Fig. 4 illustrates a kind of active pixel sensing architecture according to one embodiment of the invention.

Drawing reference numeral:

100:PIN optical diode 102:N N-type semiconductor N zone

104:P N-type semiconductor N zone 106: intrinsic semiconductor region

200: OPTICAL SENSORS

210,310: the sensing film transistor

212,312: base stage 214,314: grid

216,316: drain electrode 218,318: source electrode

220,320: optical diode

222,322: intrinsic semiconductor region

226,326:N N-type semiconductor N zone

228,328:N N-type semiconductor N zone

232: intrinsic semiconductor region 234:H type metal level

238:N N-type semiconductor N zone, 236:N N-type semiconductor N zone

244,246,248: metal level

300: display floater 330: substrate

331: common electrode 332: light shield layer

333: opening 334: chromatic filter layer

340: substrate 341: semiconductor layer

342: insulating barrier 343: the first metal layer

344: insulating barrier 345: insulating barrier

Metal level 347 in 346: the second: protective layer

348: insulating barrier 350: liquid crystal layer

360: pixel cell 362: the light sensing zone

364: viewing area 372: OPTICAL SENSORS

374: show thin-film transistor 382: read thin-film transistor

384: storage capacitors

391a～391f:N N-type semiconductor N zone

393a～393f: contact plunger

400: active pixel sensing architecture 410: pixel cell

412: read thin-film transistor 420: holding wire

430: reset transistor 440: circuit

Embodiment

Fig. 2 A illustrates the top view of an OPTICAL SENSORS 200 according to one embodiment of the invention, and Fig. 2 B is the corresponding structural representation of the OPTICAL SENSORS 200 of Fig. 2 A.Below explanation please refer to Fig. 2 A and Fig. 2 B.OPTICAL SENSORS 200 comprises sensing film transistor 210 and optical diode 220.Sensing film transistor 210 has base stage 212, grid 214, drain electrode 216 and source electrode 218.Optical diode 220 has intrinsic semiconductor region 222 and two N type semiconductor zones 226 and 228.Intrinsic semiconductor region 222 electrically connects with base stage 212 and grid 214, drain 216 and source electrode 218 then electrically connect with N

type semiconductor zone

226 and 228 respectively.Sensing film transistor 210 and optical diode 220 are for comprising low temperature polycrystalline silicon (Low Temperature Poly Silicon; LTPS) structure of material.

More particularly, the base material of the OPTICAL SENSORS 200 shown in Fig. 2 A is the low temperature polycrystalline silicon material, can be divided into three zones: intrinsic semiconductor region 232, and the N

type semiconductor zone

236 and 238 that is positioned at these intrinsic semiconductor region 232 both sides.Intrinsic semiconductor region 232 is corresponding to base stage among Fig. 2 B 212 and intrinsic semiconductor region 222.H type metal level 234 is corresponding to the grid among Fig. 2 B 214, and it is arranged on the intrinsic semiconductor region 232.The intrinsic semiconductor region 232 of being blocked by H type metal level 234 is not promptly corresponding to the intrinsic semiconductor region 222 that is used for receiving light in the optical diode 220.N type semiconductor zone 236 corresponds to the drain electrode 216 and N type semiconductor zone 226 among Fig. 2 B, and N type semiconductor zone 238 then corresponds to the source electrode 218 and N type semiconductor zone 228 among Fig. 2 B.

When irradiate light arrives intrinsic semiconductor region 232, because of the electronics electricity hole that photoelectric effect produces being moved toward optical diode 220 two ends by meeting, and conducting sensing film transistor 210 and cause positive feedback to amplify the photoelectric current of OPTICAL SENSORS 200, so can improve its photonasty effectively.In this embodiment, sensing film transistor 210 can be to be N type metal-oxide layer-semiconductor (N_typeMetal-Oxide-Semiconductor; NMOS) thin-film transistor, optical diode 220 then can be to be one N type semiconductor-intrinsic region-N type semiconductor (N_type-intrinsic-N_type; NIN) diode.Yet,, also can use P type metal-oxide layer-semiconductor (P_typeMetal-Oxide-Semiconductor according to other embodiment; PMOS) thin-film transistor is as the sensing film transistor, and this moment, optical diode then was one P type semiconductor-intrinsic region-P type semiconductor (P_type-intrinsic-P_type; PIP) diode.In view of the above, can use that lower-cost PMOS-LTPS technology realizes the OPTICAL SENSORS framework that this embodiment proposes in the display floater manufacturing.

Moreover above-mentioned sensing film transistor and optical diode can be applied in the display floater.For instance, intrinsic semiconductor region 232 (being base stage 212 and intrinsic semiconductor region 222) can be set in the low-temperature polycrystalline silicon layer of display floater, and H type metal level 234 (being grid 214) can be set in the first metal layer of display floater.And this H type metal level 234 (being grid 214) can see through contact plunger (contact plug) and electrically connect intrinsic semiconductor region 232 (being the intrinsic semiconductor region 222 of optical diode 220) by second metal level (for example metal level 244) of display floater.In addition, also can use second metal level (for example metal level 246,248) of display floater to be used as the external connection electrode in N

type semiconductor zone

236 and 238.

Fig. 3 A illustrates the top view of a display floater according to one embodiment of the invention, and Fig. 3 B is the profile of Fig. 3 A along AA ' line, and Fig. 3 C is the corresponding structural representation of the OPTICAL SENSORS among Fig. 3 A.Below explanation please refer to the 3A～3C figure.Display floater 300 comprises

substrate

330 and 340, liquid crystal layer 350 and a plurality of pixel cell 360 of a pair of corresponding setting.In order to clearly demonstrate present embodiment, in Fig. 3 A and Fig. 3 B, only cooperate explanation as representative with single pixel cell 360.Liquid crystal layer 350 is arranged between

substrate

330 and 340, and pixel cell 360 is arranged on substrate 330 and 340.Each pixel cell 360 comprises 362 and one viewing area 364, light sensing zone.Include an OPTICAL SENSORS 372 and in the light sensing zone 362 and read thin-film transistor 382.Read thin-film transistor 382 in order to read the signal that OPTICAL SENSORS 372 is produced.Shown in Fig. 3 C, OPTICAL SENSORS 372, its corresponding structure comprise a sensing film transistor 310 and an optical diode 320.Sensing film transistor 310 has a grid 314 and a base stage 312, and optical diode 320 has the grid 314 and base stage 312 electric connections of an intrinsic semiconductor region 322 and sensing film transistor 310.

Substrate

330 and 340 wherein at least one material comprise transparent material (as: glass, quartz or other material), opaque material (as: silicon chip, pottery or other material), pliability material (as: polyesters, polyalkenes, polyamides class, polyalcohols, poly-naphthenic, the poly aromatic same clan or other material or above-mentioned combination) or above-mentioned

combination.Substrate

330 and 340 among this embodiment is to be to implement example with the glass substrate.

Substrate 330 is provided with common electrode 331, and its material can be transparent conductive material, as: indium tin oxide, aluminium zinc oxide, cadmium tin-oxide, indium-zinc oxide, aluminium tin-oxide or other material or above-mentioned combination.Then corresponding respectively light sensing zone 362 and viewing area 364 on common electrode 331 and be provided with light shield layer 332 (for example black matrix") and chromatic filter layer 334.Semiconductor layer 341, insulating barrier 342, the first metal layer 343, insulating barrier 344, insulating barrier 345, second metal level 346, protective layer 347, insulating barrier 348 are formed on the substrate 340 in regular turn, and are patterned respectively and constitute OPTICAL SENSORS 372, read thin-film transistor 382, show thin-film transistor 374, storage capacitors 384, N type semiconductor zone 391a～391f and contact plunger 393a～393f.

Semiconductor layer 341 for example is siliceous polycrystalline material, siliceous crystallite material, siliceous monocrystalline material, siliceous amorphous material or above-mentioned combination.In this embodiment, the material of semiconductor layer 341 is the low temperature polycrystalline silicon material.Wherein at least one the material of insulating barrier 342, insulating barrier 344, insulating barrier 345, protective layer 347, insulating barrier 348 comprises: organic material (as: photoresistance, poly-propionyl ether (polyarylene ether; PAE), polyamides class, polyesters, polyalcohols, polyalkenes, benzocyclobutene (benzocyclclobutene; BCB), HSQ (hydrogen silsesquioxane), MSQ (methylsilesquioxane), silica hydrocarbons (SiOC-H) or other material or above-mentioned combination), inorganic (as: Si oxide, silicon nitride, silicon nitrogen oxide, carborundum, hafnium oxide or other material or above-mentioned combination) or above-mentioned combination.

More particularly, the semiconductor layer 341 of Fig. 3 A and Fig. 3 B is corresponding to base stage 312 and the intrinsic semiconductor region 322 of Fig. 3 C.The first metal layer 343 of Fig. 3 A and Fig. 3 B is corresponding to the grid 314 of Fig. 3 C, and is electrically connected at semiconductor layer 341 by second metal level 346 (seeing through for example contact plunger).The semiconductor layer 341 that is not blocked by the first metal layer 343 in the OPTICAL SENSORS 372 of Fig. 3 A and Fig. 3 B promptly is used for receiving the intrinsic semiconductor region 322 of light in the optical diode 320 corresponding to Fig. 3 C.The N type semiconductor zone 391c of Fig. 3 A and Fig. 3 B corresponds to the drain electrode 316 and N type semiconductor zone 326 among Fig. 3 C, and the N type semiconductor zone 391d of Fig. 3 A and Fig. 3 B is then corresponding to source electrode among Fig. 3 C 318 and N type semiconductor zone 328.

In this embodiment, sensing film transistor 310 is a nmos tft, and optical diode 320 then is a NIN diode.Yet, according to other embodiment, also can use a PMOS thin-film transistor as the sensing film transistor, this moment, optical diode was a PIP diode.Moreover above-mentioned pixel cell 360 includes at least one time pixel cell, and each time pixel cell is defined as all corresponding to a viewing area.That is to say that when practical application, selectively the viewing area to different colours disposes a light sensing zone respectively in a pixel cell, or in a pixel cell, a light sensing zone is shared in a plurality of viewing areas.

The start relation that following pixels illustrated unit 360 changes for light.Shown in Fig. 3 B, light shield layer 332 corresponding OPTICAL SENSORS 372 (for example being used for receiving the intrinsic semiconductor region 322 of light in the optical diode 320) have an opening 333, change for detecting pixel cell 360 light from outside.The photoelectric current that optical diode 320 produces because of irradiate light, can through and conducting sensing film transistor 310 and amplified the photoelectric current of this OPTICAL SENSORS 320, read and pass to external circuit (for example processor) via what read thin-film transistor 382 again.

For instance, when pixel cell 360 outsides are not blocked light (when opening 333 is not blocked by barrier), the photo-signal that intrinsic semiconductor region 322 makes sensing film transistor 310 obtain because of the light intensity grow that receives becomes big, reads thin-film transistor 382 this moment and can will represent the signal of clear (for example being finger or foreign object) to be sent to outside processor; When barrier stops light near pixel cell 360, intrinsic semiconductor region 322 diminishes because of the light intensity that the receives photo-signal that makes sensing film transistor 310 obtain that dies down, and reading thin-film transistor 382 this moment can have representative the signal of barrier to be sent to outside processor.

When this display floater 300 was touch control display panel, processor can be judged according to this signal and defines finger or foreign object presses on the position of which pixel cell in the display floater 300.Perhaps, when this display floater uses this kind pixel cell 360 or only use light sensing zone 362 to detect the light quantity of external environment, processor can judge whether the light quantity of display floater 300 residing external environments is enough at this moment according to this signal, even adjusts brightness of backlight module according to this signal.

Active pixel sensing (Active Pixel Sensor can be adopted in above-mentioned light sensing zone 362; APS) framework, passive type pixel sensing (Passive Pixel Sensor; PPS) sensing architecture that is suitable for of framework or other is realized OPTICAL SENSORS 372 and is read annexation between the thin-film transistor 382.Fig. 4 illustrates a kind of active pixel sensing architecture 400 according to one embodiment of the invention.A plurality of pixel cells 410 are controlled by the holding wire 420 of different lines respectively, and it reads thin-film transistor 412 and then externally sends a signal to processor by reset transistor 430 shared same circuits 440.

Though the present invention discloses as above with a preferred embodiment; right its is not in order to limit the present invention; have in the technical field under any and know the knowledgeable usually; without departing from the spirit and scope of the present invention; when can being used for a variety of modifications and variations, so protection scope of the present invention is as the criterion when looking the claim scope person of defining.

Claims

1. OPTICAL SENSORS comprises:

One sensing film transistor has a grid and a base stage; And

One optical diode has an intrinsic semiconductor region and described grid and described base stage and electrically connects, and wherein said sensing film transistor and described optical diode are the structure that comprises the low temperature polycrystalline silicon material.

2. OPTICAL SENSORS as claimed in claim 1 is characterized in that, described sensing film transistor and described optical diode are formed in the display floater.

3. OPTICAL SENSORS as claimed in claim 2, it is characterized in that, described base stage and described intrinsic semiconductor region are arranged in the low-temperature polycrystalline silicon layer of described display floater, described grid is arranged in the first metal layer of described display floater, and one second metal level of described grid by described display floater is electrically connected at described intrinsic semiconductor region.

4. OPTICAL SENSORS as claimed in claim 1 is characterized in that described grid is the H type, and is positioned on the described intrinsic semiconductor region.

5. OPTICAL SENSORS as claimed in claim 1 is characterized in that, described sensing film transistor also comprises a drain electrode and an one source pole, and the two ends with described optical diode electrically connect respectively.

6. OPTICAL SENSORS as claimed in claim 1 is characterized in that, when described sensing film transistor was a PMOS thin-film transistor, described optical diode was a PIP diode; And when described sensing film transistor was a nmos tft, described optical diode was a NIN diode.

7. display floater comprises:

The substrate of a pair of corresponding setting;

One liquid crystal layer, be arranged at described this between the substrate; And

A plurality of pixel cells, be arranged at described this on the substrate, each described these pixel cell comprises a light sensing zone and a viewing area, wherein said light sensing zone comprises:

One OPTICAL SENSORS comprises:

One sensing film transistor has a grid and a base stage; And

One optical diode has an intrinsic semiconductor region and described grid and described base stage and electrically connects; And

One reads thin-film transistor, in order to read the signal that described OPTICAL SENSORS produces.

8. display floater as claimed in claim 7 is characterized in that, described sensing film transistor and described optical diode are the structure that comprises the low temperature polycrystalline silicon material.

9. display floater as claimed in claim 7 is characterized in that, described pixel cell comprises at least one time pixel cell.

10. display floater as claimed in claim 7 is characterized in that, described viewing area comprises a storage capacitors and and shows thin-film transistor.

11. display floater as claimed in claim 7, it is characterized in that, described base stage and described intrinsic semiconductor region are arranged in the low-temperature polycrystalline silicon layer, described grid is arranged in the first metal layer, described grid is electrically connected at described intrinsic semiconductor region by one second metal level, wherein said low-temperature polycrystalline silicon layer, described the first metal layer and described second metal level be formed in regular turn described this to substrate wherein one on.

12. display floater as claimed in claim 7 is characterized in that, described grid is the H type, and is positioned on the described intrinsic semiconductor region.

13. display floater as claimed in claim 7 is characterized in that, described sensing film transistor also comprises a drain electrode and an one source pole, and the two ends with described optical diode electrically connect respectively.

14. display floater as claimed in claim 7 is characterized in that, when described sensing film transistor was a PMOS thin-film transistor, described optical diode was a PIP diode; And when described sensing film transistor was a nmos tft, described optical diode was a NIN diode.

15. display floater as claimed in claim 7 is characterized in that, described this to substrate wherein one have a light shield layer, and the corresponding described optical diode of described light shield layer has an opening.

16. display floater as claimed in claim 7 is characterized in that, described display floater is a touch control display panel.