1325049 '九、發明說明： • 【發明所屬之技術領域】 ⑯本發明有關於雷射測距儀，特別有關一種能夠校正溫 度/示移所產生之信號延遲的距離量測系統。 【先前技術】 隨著電子技術和半導體雷射器的發展，掌上型雷射相 位測距儀已經商品化，且廣泛地應用在建築、交通田地形 勘測，至内裝漬等方面。—般而言，此種測距儀係配備有 ♦發射器用以發出雷射光束’並且於掌上型雷射相位測距儀 中，係主要用於可視光譜中之光束，以便能夠對準量測點 (目標物）。測距儀内建之接收器藉由相較於發射器所發出 之光束與所接收到之光束間之時間差，即可求出與被測物 之間的距離。 ^ 一般而言’測距儀中之偵測器係使用ΡΙΝ光電二極體 或朋潰光電二極體（avalanche photodiode，APD)，將所對準 之被測物散射或反射回來之光束轉換成電性信號。藉由測 量相位變化來推算距離的測距儀會將所接收到的電性信號 疊加一混波頻率，以產生一個低頻量測信號，再將此低頻 里測彳§號之相位與參考信號之相位作比較，藉由兩者間之 相位差，即可獲知待測距離。然而，這種測距儀容易因外 在溫度的變化而影響測量精準度。 針對溫度產生之量測漂移’某些先前技術係揭露不同 之解決方法’但仍然無法完全地消除漂除或是電路太複雜 而難以應用於產品中。 0757-A22081TWF(N2)；E0106274；DENNIS 5 1325049 - 【發明内容】 . 本發明係提供一種距離量測系統，包括驅動單元，接 收具有第一頻率之第一調製信號；光發射單元，具有陽極 以及陰極，驅動單元係根據第一調製信號驅動光發射單 元，朝目標物發出第一光束；光混頻單元，用以根據具有 第二頻率之第二調製信號以及第一光束照射到目標物所反 射之光束，產生光混頻信號；電混頻單元，具有第一輸入 端耦接光發射單元之陽極或陰極上具有第一頻率之一對應 #信號，以及第二輸入端耦接第二調製信號，藉以產生電混 頻信號；以及處理單元，用以根據光混頻信號與電混頻信 號，進行相位差計算，以求出目標物與距離量測系統間之 距離。 本發明亦提供一種距離量測系統，包括頻率合成器， 用以產生第一調製信號與第二調製信號；驅動單元，耦接 • 該第一調製信號；雷射二極體，具有陽極以及陰極，驅動 單元係根據第一調製信號驅動雷射二極體，朝目標物發出 鲁光束；崩潰光電二極體，用以根據第二調製信號以及第一 光束照射到目標物所反射之光束，產生光混頻信號；以及 電混頻單元，具有第一輸入端耦接雷射二極體之陽極或陰 極，以及第二輸入端耦接第二調製信號與崩潰光電二極體 之陰極，藉以產生一電混頻信號。 本發明亦提供一種距離量測方法，包括藉由光發射單 元，根據具有第一頻率之第一調製信號，朝目標物發出光 束；藉由光混頻單元，根據具有第二頻率之第二調製信號 0757-A22081TWF(N2)；E0106274；DENNIS 6 1325049 • 以及該光束經由目標物所反射之光束，產生光混頻信號； . 根據光發射單元之陰極上之具有第一頻率之第一對應信 號，以及由光混頻單元之陰極上具有第二頻率之第二對應 信號，產生電混頻信號；以及根據光混頻信號與電混頻信 號，進行相位差計算，以求出目標物與距離量測系統間之 距離。 為了讓本發明之上述和其他目的、特徵、和優點能更 明顯易懂，下文特舉一較佳實施例，並配合所附圖示，作 #詳細說明如下： 【實施方式】 元件與傳輸線路的任何變化都會產生延遲，使得距離 量測系統之量測值產生變化。舉例而言，雷射二極體與崩 潰二極體皆是會受溫度影響的光電元件，它們容易受到自 身發熱或環境溫度的影響，而產生溫度漂移。 • 第1圖係用以說明光發射二極體之輸出功率與溫度之 關係。舉例而言，於25°C時，臨界電流約為20mA，當溫 鲁度增加至50°C時，臨界電流就會增加至約25mA，依此類 推。這是由於光發射二極體的光傳輸效率會隨著溫度增加 而下降。舉例而言，光發射二極體係可等效成並聯連接之 一電阻Rd與一電容Cd(如第2圖中所示），而其等效電容易 受到調製信號的影響。 由於光發射二極體的光輸出功率在某些應用下是需要 被固定的，所以其順偏電流將需要隨著溫度而改變。因此， 在某些驅動電路中會使用自動功率控制（automatic power 0757-A2208) TWF(N2)；E0106274；DENNIS 7 1325049 • VB之間。舉例而言，光混頻單元50係為一崩潰光電二極 -體(APD)。 電混頻單元60，具有一第一輸入端藉由電容C1與電 阻R1耦接至光發射單元40之陰極，以及一第二輸入端藉 由電容C2、C3與電阻R2耦接光混頻單元50之陰極，藉 以產生一電混頻信號S3。舉例而言，電混頻單元60係可 為一、;昆波器（mixer)。 濾波單元BPF1係耦接光混頻單元50，用以接收光混 •頻信號S2，輸出一信號S2” ；而濾波單元BPF2係耦接混 頻單元40，用以接收電混頻信號S3，輸出一信號S3”。舉 例而言，濾波單元BPF1〜BPF2係可為帶通濾波器用以得出 具有相位訊息之信號S2”與S3”。 處理單元10,用以根據信號S2”與S3”進行相位差計 算，以求出距離量測系統100與目標物200間之距離。在 某些實施例中，處理單元10係可為一數位信號處理器 (digital signal processor，DSP)，並且處理單元 10 與濾波單 ®元BPF1與BPF2之會設置類比數位轉換單元，用以將來自 濾波單元BPF1與BPF2之信號S2”與S3”，轉換成數位信 號以便處理單元10進行相位差計算，以求出距離量測系統 100與目標物200間之距離估算值。 當溫度改變時，驅動單元30與光發射元件40之工作 條件就會產生漂移，所以光發射元件40所輸出之光束S1 與第一調製信號SM之間會有相位延遲。然而，光發射元 件40之陽極與陰極上之信號，同樣會影響到此漂移的影 0757-A22081TWF(N2)；E0106274；DENNIS 10 1325049 ' 響，因此也會有產生相位延遲。舉例而言，節點N1上之 - 信號(例如電壓或電流）會與光束S1具有相同的頻率（例如 第一頻率）與相位延遲。 同樣地，當溫度改變時，光混頻單元（即崩潰光電二極 體）50之電容值會改變，造成之信號延遲會在調製信號 SL”(即節點N2上的信號)與光混頻信號S2上起相同的作 用。 換言之，由於電混頻單元60係耦接至光發射單元40 •之陰極（即節點N1)與光混頻單元50之陰極，所以電混頻 單元60所接收到的調製信號中會同樣具有驅動單元30、 光發射單元40與光混頻單元50由於溫度而產生之信號延 遲。因此，光發射單元40與光混頻單元50所受的溫度影 響將可在混頻時同時抵消。 除此之外，在某些實施例中，電阻R1係可以連接於電 容C1與光發射單元40之陽極。換言之，電混頻單元60 係採用光發射單元40之陽極上與光束S1同樣具有第一頻 •率之對應信號來行進電混頻，以清除溫度造成之信號漂移。 本發明亦揭露一種距離量測方法，其動作係參考第5 圖說明如下。 首先，藉由光發射單元40，根據具有一第一頻率之一 第一調製信號SM，朝一目標物發出一光束S1。 接著，由光混頻單元50，根據具有一第二頻率之一第 二調製信號SL以及該光束S1經由該目標物所反射之光束 S1”，產生一光混頻信號S2。舉例而言，該第二調製信號 0757-A22081TWF(N2)；E0106274；DENNIS 11 1.325049 • SL可先通過一濾波單元BPF3去除雜訊後（即調製信號SL”) - 再耦接至光混頻單元50與反射之光束S1”進行混頻產生光 混頻信號S2。 然後，根據光發射單元40之陰極上之具有該第一頻率 之一第一對應信號，以及由該光混頻單元50之陰極上具有 該第二頻率之一第二對應信號，產生一電混頻信號。 舉例而言，電混頻單元60之一第一輸入端係藉由電容 C1與電阻R1耦接至光發射單元40之陰極，並且其一第二 •輸入端係藉由電容C2、C3與電阻R2耦接光混頻單元50 之陰極，藉以產生一電混頻信號S3。由於驅動單元30與 光發射元件40之工作條件會因為溫度改變而產生漂移，所 以光發射元件40所輸出之光束S1與第一調製信號SM之 間會有相位延遲。然而，光發射元件40之陽極與陰極上之 信號，同樣會影響到此漂移的影響，因此也會有產生相位 延遲。舉例而言，節點N1上之信號(例如電壓或電流）會與 光束S1具有相同的頻率（例如第一頻率）與相位延遲。 同樣地，光混頻單元（即崩潰光電二極體）50之電容值 亦會隨著溫度改變而變化，造成之信號延遲會在調製信號 SL”（即節點N2上的信號）與光混頻信號S2上起相同的作 用。 換言之，由於電混頻單元60係耦接至光發射單元40 之陰極（即節點N1)與光混頻單元50之陰極，所以電混頻 單元60所接收到的調製信號（即第一對應信號與第二對應 信號）中會同樣具有驅動單元30、光發射單元40與光混頻 0757-A22081TWF(N2)：E0106274：DENNIS 12 1325049 單元50由於溫度而產生之信號延遲。因此，光發射單元 4〇與光混頻單元50所受的溫度影響將可在混頻時同時抵 消0 除此之外，在某些實施例中，電阻R1係可以連接於電 容C1與光發射單元40之陽極。換言之，電混頻單元60 係採用光發射單元40之陽極上與光束S1同樣具有第—頻 率之對應信號來行進電混頻’以清除溫度造成之信號漂移。 最後’根擄該光混頻信號S2與該電混頻信號S3，進 •行相位差計算’以求出目標物200與距離量測系統1〇〇間 之距離。舉例而言’處理單元10係根據光混頻信號S2，，與 電混頻信號S3”進行相位差計算，以求出距離量測系統ι〇〇 與目標物200間之距離。在某些實施例中，處理單元1〇 係可為一數位信號處理器（digital signal processor，DSP)， 並且處理單元10與濾波單元BPF1與BPF2之間會設置類 比數位轉換單元，用以將來自濾波單元BPF1與BPF2之光 _，頻信號S2”與電混頻信號S3，，’轉換成數位信號以便處理 單元10進行相位差計算，以求出距離量測系統丨與目 物200間之距離估算值。 /、 ^ 田农％ k頻皁元所接收受溫度影響後之信號（即節點 N1與N2上之信號)進行混頻，因此由溫度變化所造成 位延遲將可以自動地抵消，藉以達到消除溫度漂移的影變。 —雖然本發明已以較佳實施例揭露如上，然其並非用S以 限定本發明’任何熟知技藝者，在不脫離本發明之精神和 犯圍内’當可作些許更動與潤飾，因此本發明之保護範圍 0757-A22081TWF(N2)：E0106274;DEnnis 13 1.325049 當視後附之申請專利範圍所界定者為準°1325049 'IX. Description of the invention: • Technical field to which the invention pertains. 16 The present invention relates to a laser range finder, and more particularly to a distance measuring system capable of correcting a signal delay generated by temperature/shift. [Prior Art] With the development of electronic technology and semiconductor lasers, handheld laser phase range finder has been commercialized and widely used in construction, traffic field topographic survey, and interior staining. In general, such rangefinders are equipped with ♦ launchers for emitting laser beams' and in handheld laser phase range finder, mainly for beams in the visible spectrum, so that they can be aligned Point (target). The built-in receiver of the range finder can find the distance from the object to be measured by comparing the time difference between the beam emitted by the transmitter and the received beam. ^ Generally speaking, the detector in the range finder uses a ΡΙΝphotodiode or avalanche photodiode (APD) to convert the beam of the object to be scattered or reflected back into a beam. Electrical signal. The range finder that estimates the distance by measuring the phase change superimposes the received electrical signal with a mixing frequency to generate a low-frequency measurement signal, and then measures the phase of the § § and the reference signal. By comparing the phases, the distance to be measured can be known by the phase difference between the two. However, such a range finder is susceptible to measurement accuracy due to changes in external temperature. Measurement drift for temperature generation 'Some prior art discloses different solutions' but still cannot completely eliminate the drift or the circuit is too complicated to be used in the product. 0757-A22081TWF(N2); E0106274; DENNIS 5 1325049 - SUMMARY OF THE INVENTION The present invention provides a distance measuring system including a driving unit that receives a first modulated signal having a first frequency, and a light emitting unit having an anode and a cathode, the driving unit drives the light emitting unit according to the first modulation signal to emit a first light beam toward the target; the light mixing unit is configured to reflect according to the second modulated signal having the second frequency and the first light beam irradiated to the target a beam of light, generating an optical mixing signal; the electric mixing unit having a first input coupled to the anode or cathode of the light emitting unit having one of the first frequencies corresponding to the # signal, and the second input coupled to the second modulated signal And the processing unit is configured to perform phase difference calculation according to the optical mixing signal and the electric mixing signal to obtain a distance between the target and the distance measuring system. The invention also provides a distance measuring system, comprising a frequency synthesizer for generating a first modulated signal and a second modulated signal; a driving unit coupled to the first modulated signal; a laser diode having an anode and a cathode The driving unit drives the laser diode according to the first modulation signal to emit a Lu beam to the target; and collapses the photodiode to generate the beam reflected by the target according to the second modulation signal and the first beam. An optical mixing unit having a first input coupled to the anode or cathode of the laser diode, and a second input coupled to the second modulated signal and the cathode of the collapsed photodiode, thereby generating An electric mixing signal. The present invention also provides a distance measuring method, comprising: emitting, by a light emitting unit, a light beam toward a target according to a first modulated signal having a first frequency; and performing a second modulation according to the second frequency by the optical mixing unit Signal 0757-A22081TWF(N2); E0106274; DENNIS 6 1325049 • and the light beam reflected by the target to generate an optical mixing signal; according to the first corresponding signal having a first frequency on the cathode of the light emitting unit, And generating an electric mixing signal by the second corresponding signal having the second frequency on the cathode of the optical mixing unit; and calculating the phase difference according to the optical mixing signal and the electric mixing signal to obtain the target and the distance Measure the distance between the systems. The above and other objects, features and advantages of the present invention will become more apparent and understood. Any change in the delay will result in a change in the measured value of the distance measurement system. For example, both the laser diode and the collapse diode are temperature-dependent optoelectronic components that are susceptible to self-heating or ambient temperature and cause temperature drift. • Figure 1 is a diagram showing the relationship between the output power of a light-emitting diode and temperature. For example, at 25 ° C, the critical current is about 20 mA, and when the temperature is increased to 50 ° C, the critical current is increased to about 25 mA, and so on. This is because the light transmission efficiency of the light-emitting diode decreases as the temperature increases. For example, a light-emitting diode system can be equivalent to a resistor Rd connected in parallel with a capacitor Cd (as shown in Figure 2), and its equivalent power is susceptible to the modulation signal. Since the light output power of the light-emitting diode needs to be fixed in some applications, its forward bias current will need to change with temperature. Therefore, automatic power control (automatic power 0757-A2208) TWF(N2); E0106274; DENNIS 7 1325049 • VB is used in some drive circuits. For example, the optical mixing unit 50 is a crash photodiode (APD). The electric mixing unit 60 has a first input end coupled to the cathode of the light emitting unit 40 via a capacitor C1 and a resistor R1, and a second input end coupled to the optical mixing unit via a capacitor C2, C3 and a resistor R2. The cathode of 50 is used to generate an electrical mixing signal S3. For example, the electric mixing unit 60 can be a one; a mixer. The filtering unit BPF1 is coupled to the optical mixing unit 50 for receiving the optical mixing frequency signal S2 and outputting a signal S2"; and the filtering unit BPF2 is coupled to the mixing unit 40 for receiving the electrical mixing signal S3 and outputting A signal S3". For example, the filtering units BPF1 to BPF2 may be band pass filters for obtaining signals S2" and S3" having phase information. The processing unit 10 performs phase difference calculation based on the signals S2" and S3" to determine the distance between the distance measuring system 100 and the target 200. In some embodiments, the processing unit 10 can be a digital signal processor (DSP), and the processing unit 10 and the filter unit® BPF1 and BPF2 are provided with an analog digital conversion unit for The signals S2" and S3" of the filtering units BPF1 and BPF2 are converted into digital signals for the processing unit 10 to perform phase difference calculation to obtain an estimated distance between the distance measuring system 100 and the target 200. When the temperature is changed, the operating conditions of the driving unit 30 and the light-emitting element 40 are shifted, so that there is a phase delay between the light beam S1 output from the light-emitting element 40 and the first modulation signal SM. However, the signal on the anode and cathode of the light-emitting element 40 also affects the shadow of this drift 0757-A22081TWF(N2); E0106274; DENNIS 10 1325049', so there is also a phase delay. For example, a signal (e.g., voltage or current) on node N1 will have the same frequency (e.g., first frequency) and phase delay as beam S1. Similarly, when the temperature changes, the capacitance value of the optical mixing unit (ie, the collapsed photodiode) 50 changes, causing the signal delay to be at the modulation signal SL" (ie, the signal at node N2) and the optical mixing signal. S2 plays the same role. In other words, since the electric mixing unit 60 is coupled to the cathode of the light emitting unit 40 (ie, the node N1) and the cathode of the optical mixing unit 50, the electric mixing unit 60 receives the The modulated signal will also have a signal delay due to the temperature of the driving unit 30, the light emitting unit 40 and the optical mixing unit 50. Therefore, the temperature effects of the light emitting unit 40 and the optical mixing unit 50 will be mixed. In addition, in some embodiments, the resistor R1 can be connected to the capacitor C1 and the anode of the light emitting unit 40. In other words, the electric mixing unit 60 uses the anode and the beam of the light emitting unit 40. S1 also has a corresponding signal of the first frequency rate to travel the electric mixing to clear the signal drift caused by the temperature. The invention also discloses a distance measuring method, the operation of which is described below with reference to Fig. 5. First, borrow The light emitting unit 40 emits a light beam S1 toward a target according to the first modulation signal SM having a first frequency. Next, the optical mixing unit 50 according to the second modulation signal SL having a second frequency and The light beam S1 generates an optical mixing signal S2 via the light beam S1" reflected by the target. For example, the second modulation signal 0757-A22081TWF(N2); E0106274; DENNIS 11 1.325049 • SL can be first removed by a filtering unit BPF3 (ie, modulation signal SL)) - recoupled to the optical mixing unit 50 is mixed with the reflected beam S1" to produce an optical mixing signal S2. Then, according to the first corresponding signal on the cathode of the light emitting unit 40 having the first frequency, and the second corresponding signal having the second frequency on the cathode of the optical mixing unit 50, an electrical hybrid is generated. Frequency signal. For example, one of the first input terminals of the electric mixing unit 60 is coupled to the cathode of the light emitting unit 40 by a capacitor C1 and a resistor R1, and a second input terminal is formed by capacitors C2, C3 and resistors. R2 is coupled to the cathode of the optical mixing unit 50 to generate an electrical mixing signal S3. Since the operating conditions of the driving unit 30 and the light-emitting element 40 are shifted due to temperature changes, there is a phase delay between the light beam S1 output from the light-emitting element 40 and the first modulation signal SM. However, the signal on the anode and cathode of the light-emitting element 40 also affects the effect of this drift, so that a phase delay is also generated. For example, a signal (e.g., voltage or current) on node N1 will have the same frequency (e.g., first frequency) and phase delay as beam S1. Similarly, the capacitance value of the optical mixing unit (ie, the crash photodiode) 50 also changes with temperature, causing the signal delay to be mixed with the optical signal at the modulation signal SL" (ie, the signal at node N2). The signal S2 plays the same role. In other words, since the electric mixing unit 60 is coupled to the cathode of the light emitting unit 40 (ie, the node N1) and the cathode of the optical mixing unit 50, the electric mixing unit 60 receives the same. The modulation signal (ie, the first corresponding signal and the second corresponding signal) may also have the signal generated by the driving unit 30, the light emitting unit 40, and the optical mixing 0757-A22081TWF(N2): E0106274: DENNIS 12 1325049 unit 50 due to temperature. Therefore, the temperature effects of the light-emitting unit 4〇 and the optical mixing unit 50 will be offset by 0 at the time of mixing. In addition, in some embodiments, the resistor R1 can be connected to the capacitor C1. The anode of the light emitting unit 40. In other words, the electric mixing unit 60 uses the corresponding signal of the first frequency of the light emitting unit 40 to have the same frequency as the light beam S1 to travel the electric mixing to clear the signal drift caused by the temperature. Finally, the optical mixing signal S2 and the electrical mixing signal S3 are subjected to phase difference calculation to determine the distance between the target 200 and the distance measuring system 1 . For example, the processing unit 10 According to the optical mixing signal S2, the phase difference calculation is performed with the electric mixing signal S3" to determine the distance between the distance measuring system ι and the target 200. In some embodiments, the processing unit 1 can be a digital signal processor (DSP), and an analog digital conversion unit is disposed between the processing unit 10 and the filtering units BPF1 and BPF2 for The light _, frequency signal S2" of the filtering units BPF1 and BPF2 and the electric mixing signal S3, ' are converted into digital signals for the processing unit 10 to perform phase difference calculation to determine the distance between the distance measuring system 目 and the object 200. Estimated value. /, ^ Tiannong% k-frequency soap element receives the temperature-affected signal (ie, the signals on nodes N1 and N2), so the bit delay caused by the temperature change can be automatically offset. Attenuation of the temperature drift is achieved. The present invention has been disclosed in the above preferred embodiments, but it is not intended to limit the invention to any of the skilled artisans, without departing from the spirit and scope of the invention. Make some changes and retouching, so the scope of protection of the present invention 0757-A22081TWF (N2): E0106274; DEnnis 13 1.325049 is subject to the scope defined in the attached patent application.
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〇757-A22081TWF(N2)；E0106274；DENNIS 1325049 【圖式簡單說明】 第1圖係用以說明光發射二極體之輸出功率與溫度之 關係。 第2圖係表示光發射二極體之等效電路圖。 第3圖說明溫度與崩潰光電二極體之反向偏壓間的關 係； 第4圖係說明反向偏壓與崩潰光電二極體之電容值的 關係。 第5圖所示為本發明之距離量測系統之示意圖。 【主要元件符號說明】 10 :處理單元； 20 :頻率合成器； 30 :驅動單元； 40 ··光發射單元； 50 :光混頻單元； 6 0 .電混頻早元， BPF1〜BPF3 :濾波單元； R1〜R4、Rd :電阻； C1〜C3、Cd :電容； 100 :距離量測系統； 200 :目標物；〇 757-A22081TWF(N2); E0106274; DENNIS 1325049 [Simplified Schematic] Figure 1 is a diagram showing the relationship between the output power of a light-emitting diode and temperature. Fig. 2 is an equivalent circuit diagram showing a light-emitting diode. Figure 3 illustrates the relationship between temperature and the reverse bias of the colliding photodiode; Figure 4 illustrates the relationship between the reverse bias and the capacitance of the collapsed photodiode. Figure 5 is a schematic view of the distance measuring system of the present invention. [Main component symbol description] 10: Processing unit; 20: Frequency synthesizer; 30: Driving unit; 40 · · Light emitting unit; 50: Optical mixing unit; 6 0. Electric mixing early, BPF1 to BPF3: Filtering Unit; R1~R4, Rd: resistance; C1~C3, Cd: capacitance; 100: distance measurement system; 200: target;
Nl、N2 :節點； VB :偏壓； SM、SL、SL” ··調製信號； 0757-A22081TWF(N2)：E0106274；DENNIS 15 1325049Nl, N2: node; VB: bias voltage; SM, SL, SL" · modulation signal; 0757-A22081TWF (N2): E0106274; DENNIS 15 1325049
si :光束； S1” ：反射光束； S3 :電混頻信號； S2 :光混頻信號； S2”、S3 :信號。 0757-A22081TWF(N2)；E0106274；DENNIS 16Si: beam; S1": reflected beam; S3: electric mixing signal; S2: optical mixing signal; S2", S3: signal. 0757-A22081TWF(N2); E0106274; DENNIS 16